LSATPrepTest XLExplainedA Guide to the June, 2003 LSAT

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SECTION ILOGICAL REASONING

1. (C) Paradox

Take time to think critically about the paradoxbefore moving to the answer choices. Getting ahandle on the apparent discrepancy will let youmove confidently to the correct choice.

We know that Mark Twain and Samuel Clemens arethe same person, yet most people don’t seem toknow that Samuel Clemens is a writer. In a paradoxquestion we must ask ourselves, “How can thisbe?” Well, if most people didn’t know that SamuelClemens is Mark Twain, then we shouldn’t besurprised that they don’t know that SamuelClemens is a writer.

(A) is out of scope. The stimulus is only concernedwith the public’s awareness that Mark Twain andSamuel Clemens are writers, not whether the publichas read any of their books.

(B) provides us with information about those whodo know that Samuel Clemens is a writer. Thatdoesn’t help us with the paradox, however, as theparadox centers around the vast number of peoplewho don’t know that Samuel Clemens is a writer.

(D) mentions general opinions about authors; it is toobroad to fall within the scope of this stimulus. Also,people holding conflicting beliefs about authorsdoesn’t address the complete absence of knowledgeabout Samuel Clemens that forms the paradox.

(E) only deepens the paradox. If people know thatSamuel Clemens is Mark Twain, then why don’t theyknow that Samuel Clemens is a writer?

2. (B) Method of Argument

Paraphrase the argument in general terms as yougo. The correct answer has to match yourparaphrase to be correct.

The advertisement begins by saying that prideachieved impressive results in one instance. It thensays that Barr Motor Company has the same pride,and concludes that similarly impressive results are tobe found at Barr. This is reasoning by analogy, which(B) describes well. Predicting the answer allows us toscan the answer choices and find the only one thatdiscusses an analogy, and quickly move on.

(A) introduces the idea of repeat customers, which,because it is not a part of the stimulus, cannot besomething the author demonstrated.

(C) fails to address the Austin Stables part of thestimulus and the role it played in the author’sreasoning.

(D) says the author understates (or plays down) therole of pride in Austin Stables’ success; to thecontrary, the author emphasizes the importance ofpride to Austin Stables’ success.

(E) is an irrelevant comparison. The author is notconcerned with which organization has a longertradition of pride.

3. (B) Inference

Treat the stimulus as a set of facts. Understandeach statement individually, and think about whatmust be true based on the given facts.

We’re told the following facts: Robin doesn’t knowmorally right from morally wrong; Robin does knowlegal from illegal; Robin committed an offense;Robin knew the offense was illegal; Robin didn’tknow the offense was immoral. Based on this listof statements, she must have done something bothmorally wrong and illegal, and she must not haveknown it was wrong, but that it was illegal. (B)gives us one part of our prediction, and so isinferable.

(A) is a 180. The stimulus tells us that Robincommitted an illegal offense.

(C) is out of scope and extreme. It is far toogeneral to be a valid inference, and the word“never” is too extreme a concept for this stimulus.

(D) and (E)—specific deficiencies in Robin’supbringing and Robin’s development potential arenot addressed by the stimulus, making thesechoices out of scope.

4. (D) Method of Argument

When the question stem only asks about onespeaker, focus on paraphrasing the argument ofthat speaker before moving to the answer choices.

Anne concludes that comets flaring far from theSun must be a rare phenomenon because we’venever seen it before. Sue doesn’t challenge Anne’sevidence, but she does say that Anne’s conclusionis faulty. Sue provides additional evidence thatsuggests that the reason we’ve never seen theevent is because we’ve never been watching before,not because the event is rare. Thus she offers analternative explanation for Anne’s evidence.

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The remaining choices all say that Sue attackedsome or all of Anne’s evidence. As we saw, Sueagreed with Anne’s evidence, but challenged herconclusion.

5. (B) Assumption

A simple way to spot the disconnect between theevidence and conclusion is to look for new ideasthat appear only in the conclusion.

The conclusion of this argument is that Freudiantheories should be abandoned in favor of othermodels. As evidence, we see that some non-Freudian models predict human behavior betterthan Freudian models. The author does notexplicitly show that predictive success is a reasonto favor one theory over another. (B) makes thatimportant connection.

The stimulus is primarily concerned with thepredictive success of Freudian and other theories.(A) speaks to “causes of human behavior,” a partof the argument that is neither conclusion norcentral evidence. This is a common trap answerchoice because it is out of scope, but only in asubtle way.

(C) says that Freudian theories have had littlesuccess, but the stimulus is about comparing thesuccess of Freudian theories to other theories. Theargument requires only that the other theories arebetter than Freudian ones, not that Freudian onesare really poor predictors. Thus (C) fails to staywithin the scope of the argument.

(D) and (E) are both out of scope—(D) focuses onhow to measure predictive success and (E)mentions theories becoming “impractical,” bothideas that are not mentioned in the stimulus.

6. (E) Strengthen

Begin Strengthen questions by trying to confirmthe central assumption.

The conclusion mentions diet and the evidencediscusses dental health. The central assumptionmust link these two ideas, so our prediction is thatthe correct answer will make it more likely that dietaffects the frequency of dental problems. (E) doesthis directly.

(A) is tempting because it mentions both diet andteeth, but it focuses on a “healthy” diet, whichdoes not match our prediction; the argument isabout diet, generally. For (A) to strengthen, we

would have to assume that early humans had ahealthier diet than modern humans. When lookingfor the right answer to a Logical Reasoningquestion, remember to select the choice that mostdirectly impacts the stimulus. Don’t go for choicesthat demand extra assumptions or specialcircumstances.

(B) is irrelevant; the author implicitly recognizesthat some early humans could have had dentalproblems by saying they had fewer than we do now(which means they probably had some). This neitherstrengthens nor weakens.

(C) and (D) are 180s, as they weaken the argument.(C) weakens the argument by saying that earlyhumans had a diet that may have been similar toours in at least one way (i.e. its variety). (D) suggestsan alternative explanation (a classic weakeningtechnique) for why modern humans have more dentalproblems.

7. (B) Inference

In complete-the-blank questions, the author willhave a clearly defined argumentative structure thatsuggests what the final component will look like.

We first read that early societies had few roles andthat this results (note the word “accordingly”) instable, predictable interpersonal relations. Next, theauthor says that modern society, by contrast, hasmany social roles. Because the first half of thepassage tells us that few roles is the cause ofstability, our prediction here is that the author isabout to explain that having many roles will removethe stability. (B) matches our prediction perfectly.

“Injustice” is out of scope, and the idea “pleasant orfair” was a side comment early in the stimulus, so itis unlikely that the author’s conclusion will be about“injustice and unpleasantness” as (A) says.

(C) compares early societies and modern ones, butfails to address the author’s point about socialinteraction’s dependency on roles, and also goestoo far by saying the difference in the kinds of rolesis the “most important” difference.

(D) is well out of the scope of the stimulus. We aregiven no reason to think that the author wants toconnect technology with predicting people’s actions.

(E) is a 180. The stimulus says that early societiesdid provide its members with stable social roles.

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8. (A) Assumption

Careful translation is essential with formal logicproblems. When looking for the central assumptionin a formal logic question, arrange the evidenceand conclusion in a list, and ask yourself, “Whatadditional ‘If-then’ statement would make theconclusion follow?”

The evidence tells us that every music major (MM)is in the choir (C) and that some students at thisuniversity live off campus (OffC). The conclusion isthat no music majors live off campus. We cantranslate the argument as follows:

Evidence: If MM, then C

Contrapositive: If Not C, then Not MM

Assumption: ???

Conclusion: If OffC, then Not MM

In order to fill in this gap in the argument, we wouldneed a statement that says, “If OffC, then Not C.”(A) matches that prediction.

(B) says that none of the music majors has failedto join the choir, or, in other words, if a student is amusic major, then they are in the choir. That’s “IfMM, then C,” which simply repeats the evidence.

(C) can’t be the assumption because the word“some” is too weak to let the author concludesomething about all music majors or all off campusstudents, as he does.

(D) translates into “If Not OffC, then MM”. Ourassumption needed to use “OffC” as a trigger, butthis choice uses “Not OffC” as a trigger.

(E) is “If C, then MM” and fails to bridge the gap inthis argument. It is also problematic because itflips the if-then statement given as evidence, butdoes not negate it, which we know is one of the twocommon fallacies that show up on the LSAT againand again.

9. (C) Main Point

Main Point questions are primarily testing yourability to spot conclusions in arguments. Usekeywords, the what versus why test, and the onesentence test to find the correct answer.

When we ask “what is the author trying to prove” inthis argument (using the what versus why test) wesee that the author states, “For this reason, thepower of governments over information needs to becurtailed.” That’s a pretty strong statement. It is

highlighted by the conclusion key-phrase “For thisreason”. Additionally, the rest of the author’sstatements work to back it up. So, we’ve found theconclusion, and (C) is a close paraphrase.

The author suggests that the freedom of themarketplace of ideas could be improved, but shenever says that it is in danger, as (A) says.

(B) is a tempting choice because it comes right outof the stimulus. Remember, though, we are lookingfor the conclusion. (B) captures one of the centralpieces of evidence the author puts forward tosupport his policy recommendation.

(D) and (E), like (B), both bring up evidence theauthor uses to support his recommendation.

10. (B) Flaw

When one speaker misinterprets another’s claims,chances are the second speaker has committed ascope shift flaw.

Charlene says that using microbes forenvironmental cleanup is a limited tool becausemicrobes slow down when any given region getscolder than normal. Olaf replies by saying thatmicrobes in one cold region function as quickly asmicrobes in one warm region. Olaf hasmisinterpreted Charlene’s statement “when aregion’s temperature drops below normal” to meansimply, “when a region is cold.” In other words, hemisinterpreted her use of the phrase “belownormal” to mean “cold.” (B), therefore, is ourmatch.

The remaining choices fail to address Olaf’s scopeshift flaw.

11. (A) Strengthen

The scope of an argument often includes anelement of time. If an argument is about thefuture, the right answer must be about the future.If an argument is about the very distant past (asis #11), the right answer must be in the sametime frame.

The author gives us a hypothesis about continentaldrift and concludes that Africa and South Americawere once joined in a single landmass. We’ve got tofind the answer choice that provides support forthis idea. Scanning the answer choices, we see that(A) links the two continents by noting that a certain“rare type” of “ancient rock” appears in the placethat would have been the connection between the

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two continents. The word “ancient” properlyaddresses the geologic timescale of the stimulus,and the fact that the rock is “rare” increases thelikelihood that these bands of rock came from thesame source. Just as important, we’re talkingabout rock, which evinces a physical connection ofthe continents.

(B) and (D) identify ways in which people on bothcontinents are similar, but do not imply that thesesimilarities resulted from a continental connection(that is, there are any number of equally plausibleexplanations for the similarities), and do not specifywhen the similarities originated.

(C) discusses the weather, which has no evidentconnection to the issue of whether the continentswere once connected, and is out of the scope ofthe geology-focused passage.

(E) brings up plant-life similarities, which again: 1)are out of scope, 2) could be rooted in any of manyequally plausible causes, and 3) are apparentlymodern similarities that may or may not have beenpresent when the land masses were joined.

12. (D) Flaw

Whenever you see an argument that is based on asurvey or a study, you should start by looking forthe Flaw of Representativeness.

The author’s conclusion comes in the secondsentence. We are to believe that the public isn’tbothered by violent movies. The argument presentsa survey to back up this conclusion. As soon as westart reading about the survey, we should askourselves, “Is this survey a good representativesample?” The author all but answers the questionfor us in the last sentence by saying that therespondents are different than the general public.The respondents see tons of movies; maybe moviebuffs are less likely to be offended by violence thanare members of the general public. (D) points outthis flaw.

(A) brings up the ad hominem flaw, in which anauthor attacks the character of the oppositionrather than the opposition’s argument. This flawdoes occasionally show up on the LSAT, but theauthor doesn’t commit it here.

(B) makes a distinction that is out of scope. Theentire stimulus discusses people’s opinions aboutwhat is and is not offensive, and it never brings upobjective moral standards.

(C) is well out of scope because it introduces“antisocial behavior” as a consequence of movieviolence.

(E)—the author doesn’t say or assume that thosesurveyed based their opinions on a randomsampling of movies. The issue is that they don’tshare the same opinion as the general public.

13. (D) Strengthen

If you must strengthen or weaken one speaker’sargument in a dialogue, stick to the scope of thespeaker in question.

The argument begins with James’s argument. Heconcludes that people can evaluate complexcampaign issues. As evidence he presents the factthat Reade has commercials that discuss complexcampaign issues and that Reade is the mostpopular candidate. Maria replies by asserting thatReade’s appearance as the most competent andtrustworthy candidate is what makes him the mostpopular, and not his discussion of the issues. Tostrengthen Maria’s argument, then, we need ananswer choice that says: “Complex issues havelittle or nothing to do with it,” or “it’s all aboutappearing trustworthy and competent” (or both).(D) says the former by saying that most votersdon’t even know what Reade’s position is oncomplex issues. Clearly voters don’t go for Readebecause they understand his discussion of complexcampaign issues; they must like Reade for someother reason.

(A) and (B) mention what Reade’s opponents do orsay. They’re out of the scope of this stimulus.

(C) brings in the idea that Reade’s popularity willdiminish over time. The stimulus isn’t concernedwith what’s going to happen in the future; it onlyaddresses reasons for Reade’s current popularity.Thus (C) is out of scope.

(E) provides no real strength to Maria’s argumentbecause it uses the word “some”. How many ofthese voters think Reade is trustworthy? Tenthousand? Ten? One? Without a stronger statementabout Reade’s image, (E) falls flat.

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14. (C) Flaw

Carefully follow the logic of all if-then statements.In a Flaw question, you should first check to seewhether the author has made a mistake in herformal logic.

The author concludes that the media doesn’t havetoo much power to impose its opinions on thepublic. She backs up this conclusion with someformal logic in the next statement, which translatesinto:

“If Narrower Range of Opinions than Public on MajorIssues, Then Media Has Too Much Power.”

The author concludes that because the mediadoesn’t show a narrower range of opinions than thepublic, they must not have too much power. We seethe classic flaw of assuming that “If X, Then Y”leads to “If No X, Then No Y”. The authornegates—but forgets to flip—the if-then statement,and (C) jumps right on that common mistake. (C) ischallenging because it describes this commonfallacy in abstract language: it discusses if-thenlogic in sufficient-necessary terms by saying theauthor thinks that the fact that X implies Y meansthat Not X implies Not Y.

(A) is the classic ad hominem flaw. While this flawdoes occasionally show up as the correct choice,the author doesn’t attack anyone’s character here.

(B)—the author does assert that the mediapurveys as wide a range of opinion as the public,but this statement is part of the author’s evidence,and thus not up for attack. The weakness comes inthe author’s move from this evidence to theconclusion that the media doesn’t wield too muchpower.

(D) mentions “popular opinion.” While the opinionsof the public are a part of the argument, the logicof the argument doesn’t rest on those opinions.

(E) goes out of scope by mentioning what is“desirable”. The author says that certain criticsseem to think the media has too much power, butdesirability is never linked to the range of opinionspresented in the media.

15. (D) Flaw

If the second speaker in a dialogue misinterprets ormisunderstands the first speaker, look for a scopeshift flaw in the second speaker’s argument.

Marta begins by saying that people havecomplained about a lack of recreational areas in

the city. She asserts that turning old railway landinto walking trails may not be the most productiveway to use that land. Arthur responds with vigor,saying that the land is perfect for walkways, andthat we shouldn’t dismiss the proposal withoutreally looking into it.

Martha does not rule out providing recreationalareas; she just says we may want to createrecreational areas other than walking trails, or elsethat we may want to use different land for therecreational areas. But Arthur’s response (“…weshould not dismiss this proposal…without furtherconsideration.”) tells us he thinks Martha wants toditch the walking trail idea altogether, as (D) says.

(A)—the idea of productivity doesn’t show up inArthur’s argument, so this answer choice is out ofscope.

Neither Arthur nor Martha refers directly torecreational areas other than walking trails, thus(B) is out of scope.

Martha does say that people are complaining abouta lack of recreational areas, and Arthur does assertthat this lack is a fact (and not just a pettycomplaint). Nevertheless, the discussion concernsitself with the railway/walkway proposal. (C) missesthe point.

(E)—what is and is not possible is out of the scopeof both speakers’ arguments.

16. (D) Assumption

When a stimulus is long or complicated in anassumption question, it becomes extremelyimportant to narrow your focus to terms that don’tconnect with each other.

The author’s conclusion appears in the middle: civildisorder is more common in these despoticcountries. Why? The evidence tells us 1) that thesecountries’ leaders allow no citizen-input indetermining policies that control those citizens, and2) that when people don’t understand the purposeof laws that control them, they tend toward civildisobedience.

In this passage, the two pieces of evidence aredisconnected from each other: the first talks aboutinput, and the second talks about understanding. Asa result, our prediction is that the answer will linkthese two concepts by saying something like “inputis necessary for understanding.” (D) fits the bill.

The author never brings up the idea of rationality,so (A) is out of scope.

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(B) speaks to the effectiveness of the press atconveying ideas, an idea that is also out of scope.

(C) is out of scope; the argument isn’t concernedwith using security forces to quell civil disorder.

(E) is out of scope because it focuses on the wrongkinds of countries. The author says that peopletend towards greater disorder when they don’tunderstand the restrictions placed on them. It neversays anything about the prevalence of civil disorderin societies with free elections or a free press. Theauthor simply says that societies without thesefeatures have even more disorder, regardless of theamount of disorder present in countries with thefeatures.

17. (E) Weaken

Look to weaken a causal argument such as “Xcaused Y” by using one of the three classicalternatives:

“Y caused X”

“Z caused X and Y”

“X and Y are not related”

The conclusion includes a causal conclusion: lowermagnesium increases your risk of heart disease,stroke, and hypertension. The author’s evidence isthe fact that people with those diseases haverelatively low levels of magnesium in their blood.We’re given a correlation as evidence, and expectedto believe that there’s a causal connection. That’sa classic LSAT argumentative mistake, and we’regoing to look for an answer choice that fits one ofthe classic ways to weaken a causal argument. Wepredict one of these three scenarios:

“Heart disease, stroke, and hypertension causelower magnesium levels”

“Some other condition causes heart disease,stroke, hypertension, and low magnesium levels.”

“The correlation between magnesium and thesedisorders is coincidence.”

Scanning our answer choices, we see that (E)matches the first scenario.

(A) introduces several ideas that are out of scope,including “prosperous countries” and “generallyadequate diet”. We’d have to stretch our logic tothe breaking point to link those ideas to thestimulus.

Similarly, (B) and (C) are out of scope because theideas of aging and sodium intake aren’t addressed

in the stimulus. As for (B), we may think, “But hey,in real life, I’m pretty sure sodium increases bloodpressure, so that’s in the scope.” But does “bloodpressure” actually appear in the passage? Notquite: although the main symptom of“hypertension” is high blood pressure, this is notcommon knowledge—it is somewhat specializedknowledge. More importantly, even if everyone knewabout that connection, it only addresses one of thethree ailments. So, (B) requires at least twoadditional assumptions (that sodium does increaseblood pressure, and that blood pressure is relatedto all of the ailments mentioned). And even then,for (B) to strengthen, we still need a thirdassumption: that drinking water with lessmagnesium will lower magnesium levels in theblood. That’s way too many leaps! But notice thatanswer choices are often carefully crafted to get usto make them without noticing it. We have to becareful about analyzing our own line of reasoningwhen we evaluate these choices.

(D) might weaken the argument if we also knewthat this inhibitory action prompted doctors to tellpatients to stop taking magnesium while beingtreating for hypertension and heart disease; we’dalso have to add the idea that the ingestion ofmagnesium supplements was an important sourceof magnesium. Again, too many additionalassumptions.

18. (B) Principle

Principle questions require you to take thespecific case in the stimulus and find the answerchoice that is the general case. Stick close to thescope of the stimulus when making yourgeneralizations.

Start tackling principle questions by finding andfocusing on the author’s conclusion . The bookstoreowner values variety, and he advocates thatconsumers “only” behave in such a way as to fostervariety. A quick scan of the answer choices showsus that (B), (D), and (E) are generalizationscouched in terms of consumer behavior and variety.(B) is the one that gets us where the author isgoing, namely, that consumers should onlypatronize stores that have variety, and should notpatronize stores that don’t.

We can eliminate (A) and (C) right away becausethey miss the scope of the author’s argument bynot advocating for a particular behavior on the partof consumers.

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(D) is about bookstores “deliberately” forcing otherstores out of business, a concept that is out ofscope. Additionally, the author is concerned withcompetition only insofar as competition impactsvariety.

(E)—the author never discusses consumers whohave no access to independent booksellers.

19. (C) Assumption

You must link the terms of the evidence with theterms of the conclusion to answer an assumptionquestion.

The author begins his argument with theconclusion: “…anger in response to insults isunreasonable...” He backs this up by saying thatinsults should prompt either pity or gratitude. Theassumption appears to be that one cannotappropriately feel both 1) anger and 2) either of pityor gratitude. (C) addresses this assumption bysaying that anger is never a reasonable reaction toactions that merit pity or gratitude.

(A) is out of scope because it uses the term“hostile reactions” instead of “anger in responseto…” Although “anger” and “hostility” are related,for a reaction to be hostile, one must express thathostility to another party. The argument isconcerned strictly with the internal emotional stateof the person reacting, thus hostility is out ofscope.

(B) is close, but it misses the pity-ignorance part ofthe evidence, instead going beyond the scope toinclude one’s response to all “useful information.”

(D) merely repeats the evidence that gratitude andpity are reasonable reactions to insults.

(E) is a distortion. Pity is used in the argument asa reaction to receiving an insult from someone whothinks you have an undesirable characteristic. (E)discusses pity as a reaction to the person with theundesirable characteristic, thus distorting the roleplayed by “pity” in the argument.

20. (D) Parallel Flaw

Sometimes a stimulus argument lends itself toalgebraic translation.

The argument essentially argues that we can do X(double a car’s fuel efficiency), and we can do Y(meet a specific safety standard), so we can doboth X and Y simultaneously, and therein lies theflaw. The author fails to recognize that “doing X’

might make it impossible to “do Y,” or vice versa. Inthe same way, (D)’s author improperly concludesthat a novel can simultaneously get raves and hugesales simply because each of those individualoutcomes is possible.

(A)’s conclusion is that two conditions cannot bothbe true—(A) is an argument fraught with negativestatements that have no parallel in the stimulus.

(B)’s conclusion contains the cause-and effect term“because,” but there’s no cause-and-effectrelationship like that in the stimulus.

(C)’s citation of Susan and Nathan’s concreteclaims don’t parallel the original’s: “it is cold” and“it is snowing” are not parallel to “we canmanufacture” and “we can produce,” because theword “is” is concrete, whereas the word “can” is anexpression of possibility.

(E)’s conclusion that “X will someday happen” is aconfident prediction, but the original never makes aprediction of any type.

21. (E) Assumption

Assumption questions will always introduce a new,unsupported idea in the conclusion. The rightanswer choice will connect that new idea to theterms in the evidence.

The conclusion of this argument is neatly set offwith the keyword “therefore”. We see that pizzeriasuse direct-mail more effectively than otherrestaurants. Why? The evidence tells us they aregood at collecting and sorting consumerinformation. So we predict that the centralassumption is going to link using direct maileffectively and collecting consumer information.And, in fact, (E) links these ideas perfectly.

(A)—it’s not important whether restaurants otherthan pizzerias are easily able to collect thisinformation; the only thing that matters is whetheractually collecting it makes restaurants moreeffective users of direct mail.

(B) misses the scope by talking about what usingdirect mail “requires,” rather than whether thecustomer information is related to using direct mailmore effectively than other restaurants.

(C) fails to address the conclusion at all by onlyfocusing on the evidence.

(D)—the author says that pizzerias collectconsumer information more often than any otherrestaurants, but she never discusses restaurants

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that cannot collect such information at all, and istherefore out of scope.

22. (C) Inference

Carefully translate all if-then statements intousable shorthand. If you see connections betweenthese statements, you can pre-phrase your answerchoice; if not, move to the answer choices.

Let’s translate this stimulus into if-then statements:

#1: If HS (highly successful), then WO and SM.

#2: Contrapositive: If Not WO or Not SM, then NotHS

#3: If WK (well known), then HS.

#4: Contrapositive: If Not HS, then Not WK

#5: If SM, not RC (regret choices).

#6: Contrapositive: If RC, then Not SM.

These three statements link end to end as follows:

If you’re well known, then you’re highly successful(#2), and if you’re a highly successful, then you’rewell organized and self-motivated (#1), and if you’reself-motivated then you don’t regret your careerchoices (#3). In terms of the statements above wehave:If WK, then HS and WO and SM and Not RC.

With this linked statement, let’s turn to the answerchoices.

(A) says: “If SM and Not HS, then Not WO”.According to the stimulus, “Not WO” is never aresult, so no trigger could ever let us conclude “NotWO”. Thus (A) cannot be a valid inference.

(B) says: “If WO and Not HS, then SM”. Thestimulus has “SM” as a result only when “HS” isthe trigger. This choice says “Not HS” and thus isnot a valid inference.

(C) says: “If WK, then Not RC”. This is a summaryof our linked statement above, and is a validinference. Don’t let the fact that (C) starts with“no” blur the issue: “no WK are people who RC”means that if someone is WK, then he’s not an RC.

(D) says: “If Not WO, then RC”. The stimulus neverincludes “RC” on the “then” side (i.e., as a result),so this cannot be a valid inference.

(E) says: “If Not RC, then HS”. The stimulus neverhas “Not RC” as a trigger, so nothing can beconcluded given than piece of information. Thus (E)is not a valid inference.

23. (A) Parallel Reasoning

When two arguments are parallel, they don’t haveto mention evidence and conclusion in the sameorder; reversing them in the right answer is a wayin which the test maker can make the questionharder.

The author says that a correlation (i.e. betweenvigorous exercisers and less illness) doesn’t meanthat the former causes the latter, and her evidenceis that the reverse is equally plausible (i.e. goodhealth at least partially leads a person to exercise).That (A) begins by mentioning its evidence firstdoesn’t affect its standing as the right answer. Inthe same way as the stimulus, it argues thatvoracious reading (one half of a correlation) doesn’tnecessarily cause verbal skills (the other half),because it’s just as likely that the reverse is true:The verbally skillful tend to read.

(B) starts with a more complex scenario (“musicalskill and math skill are produced by abstraction”),an early sign that (B) is not following (A)’s roadmap, and (B) drifts even more far afield after thecomma: There’s no parallel in the stimulus to“some mathematicians are not skilled musicians.”

(C)’s two terms (“one’s choice of dress” and “howfriends dress”) are joined by a third (“one’s stylepreference”), but the stimulus and (A) only featuretwo terms each.

(D), like (C), adds a third term (“frequency of play”)to its original two (“height” and “performance”). Inthis way it is more complex than the stimulus,hence not parallel.

(E) deals with a possible single cause for twoseparate effects, whereas the stimulus isconcerned with one condition causing another.

24. (C) Inference

Inference questions containing formal logictypically work just like formal logic combinationsin Logic Games. Paraphrase facts in inferencequestions as you read, understanding eachstatement individually, and then consider whetherany of the statements combine.

We can translate the stimulus as follows:

#1 If FS, then LS and No WF.

#2 Contrapositive: If WF or No LS, then No FS.

#3 If CL, then WF

#4 Contrapositive: If No WF, then No CL.

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#5 If TS, then CL.

#6 Contrapositive: If No CL, then No TS.

The stimulus concludes by telling us that the planthas LS and CL. Scanning through our if-thenstatements above, we know that this plant with CLmust also have WF (line #3), and if it has WF, thenin has no FS (line #2). LS is not a trigger, so wecan’t conclude anything else. Scanning the answerchoices, we see that WF and no FS is (C), which isthe correct choice.

25. (B) Role of a Statement

When you read Role of a Statement stimuli, findthe conclusion and evidence, and check to seewhether the statement in question fills one ofthose roles first.

The author’s argument concludes that engineersget too little credit for inventions. As evidence, weread that engineers have to work hard to translatean inventor’s insight into something usable. Thestatement from the question stem isn’t a centralpart of the author’s argument. In fact, it isconcession that sometimes inventors don’t use theservices of other engineers. So, as (B) says, it isan admission that the problem of under-appreciatedengineers isn’t always the case, becausesometimes inventors do the engineering workthemselves.

(A)—the argument does not really have a“theoretical” (i.e., speculative or abstract) aspect. Itis entirely concerned with what happens in practice.

(C) describes evidence, however this statementdoesn’t serve as evidence or conclusion.

(D)—“Concedes” is tempting, but the argumentnever says that the inventor/engineer distinction isunclear (to the contrary, it seems to be based on aclear distinction between the two kinds of work),just that the distinction doesn’t apply in every case.

(E) uses the word “solution” but the statement inquestion doesn’t solve any problem; if there’s any“solution” in the stimulus it’s just therecommendation that engineers deserve morecredit.

SECTION I

9

Section IILogic Games

Game One: “Making Soup”Situation: In a kitchen, making soup. Entities:Ingredients for the soup. Action: Sequencing theorder of the ingredients. Limitations: Six ingredientsare being used in order, and the rules relate theentities to specific slots. That tells us this is astandard sequencing game, with a 1 to 1 match upof entities to slots. List the entities and then theslots, numbered 1 through 6, for this game.

Our first two rules come in if-then format.Remember to note both the rule and thecontrapositive for each of these rules. Rule One isa straightforward if-then which can be noted as “IfM3, then L6” and “If L NOT 6, then M NOT 3”. RuleTwo, however, is a bit trickier. The rule is “If Z1,then L…O”. The contrapositive is “If O…L, then ZNOT 1”.

Rule Three is a negative rule which can be noted byjotting down “NO K” and “NO T” below slot 5. Makesure this is prominent in your sketch, as negativerules are particularly easy to overlook when workingthrough the game.

Rule Four is a big one. We’re told that M comesbefore K or T, but not both. Remember to analyzebefore you draw each rule. If M comes before one(but not both) of K and T, that means the othermember of the pair must come before M. Thus wecan note: “K/T…M…T/K”.

In Step Four of the Kaplan Method, we should belooking for common elements. We see that M ismentioned in rules one and four. If M is third, thenL must be sixth. We know that K/T must go after M,but that K/T can’t go in slot #5. This means thatwhen M is third, the only room for K/T is slot #4.Add this deduction to your sketch.

We also see that L is mentioned in rules 1 and 2. IfZ is in slot 1, then L can’t be last. Knowing that Lcan’t be last tells us that M can’t be 3rd. Add thisdeduction to your sketch as well. Our MasterSketch is somewhat open, but we have enoughinformation to begin tackling the questions:

1. (D) AcceptabilityCompare the rules to the choices.

Rule One is violated by (B), which puts M third, butputs L fifth.

Rule Two is violated by (E), as it puts Z first andthen puts O before L.

Rule Three is violated by (A), because it puts Tfifth.

Rule Four is violated by (C), because it puts Mbefore both K and T.

2. (C) CANNOT be trueWe are asked which entity could not possibly gofirst. We are given no new information, so we knowthe right choice will be one that violates our MasterSketch. We see that M is among the answerchoices, but that our sketch includes the fact thateither K or T must come before M. Thus M couldnot be first, and (C) is correct.

3. (A) Must be true / “If” questionBegin by building a small sketch just for thisquestion. Note that L will be last. Our deductionstell us that Z cannot come first because O mustcome at some point before L. We can also deducethat M cannot come fourth. This would demandputting K/T in slot 5, which is not permitted. Jotdown “No M” below slot 4. Knowing this, we can goto the choices, looking to find something about Z orM. Choice (A) essentially says that Z cannot befirst, and thus must be true.

K L M O T Z

__ __ __ __ __1 2 3 4 5 6

__

No KNo T

M3 L6 K/T4L NOT 6 M NOT 3 Z1 L…O M NOT 3 O…L Z NOT 1K/T…M…T/K

PREPTEST 40 EXPLAINED

10

4. (C) Acceptability (Partial)Use the rules to eliminate choices in partialacceptability questions. After that, work through theremaining choices to find the acceptable choice.

Rule 1 eliminates (A) because it puts M in slot 3and L in slot 2.

Rule 2 eliminated (D), which puts Z first and L last.

Rule 4 eliminates (B) and (E), leaving only (C). (B)is eliminated because we know that either K or Tmust follow M, however (B) puts M in 4 and L in 6.This only leaves slot 5 for either K or T, whichcannot happen due to rule 3. (E) is eliminatedbecause it puts Z in 1 and M in 2, which doesn’tleave a space for K or T to come before M.

(C) puts O in slot 2 and M in slot 5. With M inslot 5, we can put T/K in slot 6. We know that Zcan’t go in slot 1, because there would be no roomfor L to come before O. We haven’t broken anyrules, so (C) could be true.

5. (D) CANNOT be true / “If” questionStart by jotting down a new sketch for thisquestion. Put Z in slot 1. We know that oursequence must contain “L…O” so take note ofthat. Our remaining entities are those in the“T/K…M…K/T” sequence. We know that M can’tgo in slots 2 or 6, as there would be room for K/Tor T/K to fit before and after the M. We also can’tput M in slot 3, because that would demand that Lgo in slot 6. We know that L comes before O, so itcan’t be in slot 6. That leaves slot 4 or 5 for M. Jotdown arrows leading to those slots for M. Now lookthrough the answer choices trying to find the onethat cannot be true. (D) and (E) should catch oureye as they mention slot 4, and we made adeduction about M going in either slot 4 or 5. If, as(D) says, L was in slot 4, M would have to go inslot 5. But then both O and T/K would need to gointo slot 6. That can’t happen, so (D) must befalse, and is the correct answer.

SECTION II

11

Game Two: “Ranking Medicines”Situation: A consumer group’s office. Entities:Seven cold medications. Action: Selecting five ofseven medications, and then ranking them from 1st

through 5th. Limitations: Exactly five medicationswill be selected, and two rejected. Thosemedications selected will be ranked from 1 through5, with no ties. Thus our game is a hybrid ofselection and strict sequencing.

Begin by listing the entities, and noting “Exactly 5”to remind yourself of the game’s limitation. Avertical list makes the most sense when the gameasks us to rank the entities, so list 1 through 5vertically in your scratchwork.

The first two rules are concrete ones that can bebuilt right into our framework. Jot down L in slot #2,as Rule One tells us, and put “F/G” in slot #1, asRule Two says. We should keep in mind that we areselecting as well as sequencing, and that we willneed to note rules about selection as well as rulesabout the rankings. Rule One tells us that L isdefinitely selected, so we should circle L to remindus of that fact.

Rule Three says that I is selected. Circle I in yoursketch to take note of this rule.

Our next three rules all come in if-then form. Notethem carefully:

Rule Four says if H and G are selected, the H ranksabove G. Use the ellipsis to note that H is above G,since the rule doesn’t tell us how far above.

Rule Five is similar to rule four because it says thatif both K and F are tested, then K is above F.

Our final rule, Rule Six, only gives us informationabout the selecting portion of this hybrid game. IfM, then F & H is a simple way to note this rule.

Once we’ve noted all of the rules, our sketchshould look like this:

During Step Four of the Kaplan Method we shouldmake deductions by looking for common elements.F and G show up in several rules each, so weshould begin by looking at those two entities.

We know that the top slot is going to go to either F orG. That’s an excellent place for us to start setting uplimited options. Set up two options: Option I has F inslot #1, and Option II has G is slot #1. You can put Lin slot #2 immediately, in accordance with Rule One.

In Option I, we know that we cannot select K.Selecting both K and F would mean K ranks aboveF, and that can’t happen with F in slot #1. Ourremaining three slots will have to be filled by I andthen two of G, H,or M. We’ll have to eliminate oneof those three as we work with this option.Remember, selecting M means selecting H, and soyou can never select M and G together.

In Option II, we know that we cannot select H.Selecting both H and G would mean H ranks aboveG, and that can’t happen with G in slot #1. RuleSix’s contrapositive tells us that crossing off Hmeans crossing off M. Our remaining entities are K,I, and F. Since we’re going to be choosing both Kand F, we know that K must rank above F. Slot #3,therefore, can only include K or I. Note this in slot#3. Similarly, slot #5 can only include F or I. Slot #4can include any of the three entities.

Adding these two deductions and the contrapositiveof the last rule yields the following sketch:

6. (D) AcceptabilityCheck each rule against the choices:

Rule One is violated by (A), which puts I second.

Rule Two is not violated.

Rule Three is violated by (B), which does notinclude I.

123 45

F/GL

H G

K F

&

&

M F & H

H

G K

F

……

Op I Op II123 45

F L______

__ G L K/I/FF/I____

________

No H or No F No M

F G H I K L MEXACTLY 5

K/I

123 45

F/GL

H G

K F

&

&

M F & H

H

G K

F

……

F G H I K L MEXACTLY 5

PREPTEST 40 EXPLAINED

12

Rule Four is violated by (B), which we have alreadyeliminated.

Rule Five is violated by (E), which puts F above K.

Rule Six is violated by (C), which includes M butdoes not include H.

(D) is the only remaining choice and must becorrect. Circle this as an acceptable list of entities.

7. (C) Could be trueThis question stem doesn’t give us anything new towork with, so we’ll have to proceed through theanswer choices until we find the one that doesn’tviolate any rules.

Use our master sketch and look at Option II. Herewe see that I could be in third place, while F couldbe in fifth. This happens to be answer (C). Taking astep back to evaluate the information you alreadyhave can save you valuable time on test day.

If you did not see that I could rank better than F,begin to evaluate the answers:

(A) says that we choose both G and M, and that Granks better than M. This could not be the case. Ifwe choose M, then we must also choose F and H.This means our roster has to include G, M, F, H, I(always chosen), and L (always chosen), which isone entity too many.

(B)—if H ranks better than F, then F must not bechosen first. That means we’re working in Option II.However, Option II shows us that H can’t bechosen. Thus (B) cannot be true.

(C) could be true. Looking at our deductions, wesee that I could rank over F in Option II.

On Test Day, we should stop working through thechoices, but for completeness’s sake, we willinclude:

(D)—for K to rank better than G, we would have towork in Option I. However, Option I precludes K.Thus (D) cannot be true.

(E) is wrong for the same reason (A) is wrong. ForM to rank better than G, we must work in Option I.M demands that we choose F and H. Our rosternow includes M, G, F, H, I (always chosen), and L(always chosen). This is one entity too many.

8. (A) Must be trueWe’re asked which entity must be selected.Checking each choice against our two options, wesee that F is the only entity which must be selectedin both answer choices.

9. (E) Complete and Accurate ListA quick glance at Option II tells us that either F or Icould be ranked last. That piece of info lets useliminate (A), (B), and (C) right off the bat. Lookingat (D) and (E), we see that K is present in (D). Theonly option that includes K is Option II, and K couldnot be last in Option II. Thus (D) is out as well.That leaves (E) as the correct choice.

10. (B) Could be true EXCEPTThe “If” to this question stem doesn’t preclude oneoption or the other, so our sketch just for thisquestion will have to include both options. ForOption II, the roster (in order) is: G, L, I, K, F. InOption I, we know our roster starts with F, L, I, butthe remaining two slots are open for G, H, and M.Looking for the one choice that violates our sketch,we see that (B) says that K ranks better than G.This couldn’t happen in Option I (no K allowed!), norcould it happen in Option II (G was first, K fourth).Thus (B) must be false and is the correct choice.

SECTION II

13

Game 3: “Zephyr Airlines Cities”Situation: Zephyr Airlines’ nonstop routes. Entities:The five cities that the airline serves. Action: Toconnect—or determine the nonstop connectionsbetween—the five cities. Limitations: Each of thefive cities is connected to at least one other of thecities—which means that we’ll never haveVancouver, for instance, sitting out thereunconnected.

This game involves matching one city with another.A Matching game in which there is only one type ofentity is a special game type called a “Mappinggame”. Let’s use a single straight line to indicateeach two-way connection, and there’s no reasonwhy we can’t arrange the cities arbitrarily like so:

As we learn of actual connections we can just drawthem in.

Rule One means that there will be exactly onestraight line connecting Montreal with...which city?No way to tell, but perhaps the words “1 ONLY”next to “M” on the map will remind us thatMontreal is involved in only one two-way connectionfor Zephyr.

Rule Two, a negative rule (hence not as helpful),tells us never to draw a line between H and T. Jotthat down next to each of those letters (“NO H,”“NO T”) as a reminder.

Rule Three is an if-then rule and (as usual) must beinterpreted properly. Whatever city or cities weconnect with H, says Rule 3, must also beconnected with T. (So, for instance, if we have aP—H connection, we will have a P—T connection aswell.) The contrapositive would also hold: If a citycan’t be connected with Toronto, then it can’t beconnected with Honolulu.

Rule Four is one more if-then. If there’s a P—Tconnection, then there won’t be a P—V connection.And if we ever have P—V, we won’t have P—T.

Four fairly abstract and slippery rules; four rulesthat will elude us unless we proceed carefully andwith precision. We should begin by noting anegative deduction: since Rule Three says that any

city connected with Honolulu must also beconnected with Toronto, and since Rule One saysthat Montreal has only one connection, it followsthat “M—H” will never appear in the game.Montreal can’t support the twin connections thatRule Three demands.

Looking at our sketch so far, we see that H cannotconnect to T, and it cannot connect to M. Weremember that we must always turn negatives intopositives. We should ask ourselves, “Okay, sowhere can H connect?” As our overview told us, noentity is going to be left out in the cold with noconnections. H’s two options are V and P. Whilethese options won’t nail down tremendous amountsof information, there are the only possibilities for H,and thus we should draw them out.

In Option I, V and H are connected. Since V isconnected to H, V must also be connected to T.

In Option II, P and H are connected. Since P isconnected to H, P must also be connected to T. AP-T connection means no P-V connection, so note“No V” and “No P” next to P and V, respectively.

In Option III, H is connected to both P and V. Both Pand V need to be connected to T, in accordancewith Rule Three. Once again, the P-T connectionmeans no P-V connection. Note this.

Our final sketch should now look like this:

H

V M

T P

PREPTEST 40 EXPLAINED

14

11. (A) AcceptabilityRule 1 is violated by (B). Montreal can have butone connection, not two.

Rule 2 is violated by (E). H—T is never an option.

Rule 3 is violated by (C). Montreal, connected withHonolulu there, would need to be connected withToronto as well. Of course, that would cause adifferent violation, but no matter. As written, (C) isimpossible.

Rule 4 is violated by (D). Simultaneous P—T andP—V connections are prohibited. All that’s left is(A), the right answer by default.

12. (B) Could be trueThe abstract if clause, “Exactly three cities areconnected with Philadelphia,” demands that youpose the concrete question: “Which three?” AndPhiladelphia reminds us of Rule 4, which prohibitssimultaneously connecting P—T and P—V. Clearly,then, the three cities in question will have to beMontreal; Honolulu, and either Toronto orVancouver. That’s it for Montreal (Rule 1), sochoices (A), (C), and (D) can be thrown outinstantly. Next: We have a city connected withHonolulu—Philadelphia—which (Rule 3) means thatit must connect with Toronto as well. So much forthe dotted lines: P will for sure connect with H, M,and T; (E) is impossible, and that leaves (B) as thepossible connection and the right answer. H—V isquite possible, so long as V—T occurs as well.

13. (A) CANNOT be trueWhen you see a question stem as open as thisone, begin by checking your deductions. The onlypair that could never be connected (in ourdeduction) is H-M. Fortunately, that’s (A) and ourwork is done.

14. (A) Could be trueWhen we try out (A), we can make it work andavoid any further aggravation. The only option whereM and P can be connected with no otherconnections is Option I. Connect M to P and we canstop; every city has a connection and we’ve brokenno rules. On Test Day you should stop and moveon. For the record:

(B) won’t work because it would leave Honoluluunconnected (reread Rule Three—any cityconnected with H must also be connected with T,but in (B) that’s impossible).

(C), for the very same reason as (B), is impossible.There’s got to be at least one city connected withboth H and T, and (C) precludes that happening.

(D) won’t fly either. (D) leaves Honolulu out in thecold, forcing a violation of either Rule 1 (if weconnected M—H and M—T), or Rule 2 (if weconnected Honolulu with Toronto).

(E), too, leaves Honolulu with no possibleconnections. Some city needs a connection withHonolulu, and that city must connect with Torontoas well (Rule Four), but (E) doesn’t provide for one.

H

V M

T P

No H(Only 1)

No H

X–H X–TP–T No P–VP–V No P–T

Option INo TNo M

H

V M

T P

No H(Only 1)

No H

Option IINo TNo M

No V

No P

H

V M

T P

No H(Only 1)

Option IIINo TNo M

No V

SECTION II

15

15. (D) Could be trueThe stem asks us to create a new sketch in whichP—T are connected and P has no otherconnections. We’ll have to work on Option I. Westart by connecting P and T. The only city that stillneeds a connection is M, so we’ll draw a dottedline from M to V and to T. The only choice whichdoesn’t violate our new sketch is (D). There couldbe either two or three cities connected to Toronto,so (D) could be true.

(A) is false; Toronto gets at least two connections,with Philadelphia and with Vancouver.

(B) is false; we already have V—H and V—T drawninto our sketch.

(C) is false; the one and only Honolulu connectionis with Vancouver.

(E)—Toronto’s maximum is three.

16. (B) Maximum number of possibilitiesThe maximum number of possible connections mustfirst take into account Rule 4, which says that ifone connection is made, another one is not. Thereare only three possibilities based on Rule 4; let’swork out each.

If neither P—V nor P—T are present, thenVancouver will have to be connected with bothHonolulu and Toronto, and to link Philadelphia intothe matrix we’ll have to connect M—P. That’s atotal of three.

If we connect P—V rather than P—T, then Vancouverwill have to be connected with both Honolulu andToronto (Rule 3), and Montreal will get its singleconnection with some city, for a total of four.

If we connect P—T rather than P—V, then Honolulucan have two connections (with Vancouver and withPhiladelphia); Vancouver would have to beconnected with Toronto (Rule 3); and Montreal’sconnection would be with either Toronto orVancouver. That’s a total of five...and the highestnumber, so (B) is correct.

17. (C) Must be true“Which city,” it’s your job to ask, “is the one thequestion is talking about—the one connected withthe other four?” Can’t be Montreal (Rule One); can’tbe Honolulu (Rule Two); can’t be Philadelphia (RuleFour); and can’t be Toronto (Rule Two). It follows,then, that question 17’s sketch must featureVancouver connected with the other four cities. (C)

represents one of those four connections; it mustexist, so (C) is the right answer.

(A), (D), and (E) are impossible because V—M fillsMontreal’s allotment.

(B)—the presence of “V—P” makes “P—T”impossible (Rule 4), and without aPhiladelphia/Toronto connection, aHonolulu/Philadelphia connection is prohibited(Rule Three).

PREPTEST 40 EXPLAINED

16

Game 4—”Behavioral Study Animals”Situation: The preparation for a behavioral study ofanimals. Entities: The available animals, three ofeach of three species. Action: To select theanimals that will be studied. A total of six is sought.Limitations: We’ll pick six out of nine, so at alltimes, a total of three will be rejected. This is aclassic “grouping game of selection,” and theclassic Master Sketch involves a list of the entitiesthat will allow us to circle the selected ones and Xout those rejected:

MONKEYS pandas raccoonsF G H k l n T V Z

Note how the labels and different kinds of lettersmake it easier to distinguish between the speciesand to keep track of which is which. These areenormously helpful techniques.

Rules One and Two are of the same type and canbe analyzed together. In each, we’re told a pair ofentities that can’t be chosen together. Of course,we can’t infer “one or the other” for each pair,because it’s possible that neither is chosen. So ourscratchwork simply needs to act as a warningagainst selecting each “toxic” pair:

NEVER F&H NEVER n&T

Rules Three and Four, too, are of the same type. Ineach, we’re told that selecting an entity meansselecting another one. And in each, thecontrapositive would tell us that if the “result”entity is rejected, the “trigger” entity will be as well.Your scratchwork should look like so:

If H k

No k no H

If k n

No n no k

Rather than spinning our wheels building on merehypotheticals (“If I pick H, then we have to pick kand reject F, and then pick n...etc. etc.”) let’s justproceed into the questions, confident that they willprovide concrete information that will act as a moresolid foundation.

18. (D) AcceptabilityUse the rules to reject the wrong choices inacceptability questions.

Rule One is violated by (B), which selects F and Hsimultaneously.

Rule Two is violated by (A), doing likewise with nand T.Rule Three is violated by (E), in its selection of Hwithout k.

Rule Four is violated by (C), in its selection of kwithout n. That leaves (D) as the right answer.

19. (C) Could be trueA list of the nine letters needs to have H and lcircled, and then we proceed to the choices.Selecting H means crossing out F (Rule One) andselecting k (Rule Three), which in turn mandates theselection of n (Rule Four). Choosing n knocks outT of our roster (Rule Two), so here’s where we are:four animals selected for sure; two (F and T)rejected; and three remaining (G V Z ) to fill out thegroup of six. Any two will do, so (C) is eminentlypossible while the other four all contradict oursketch.

20. (C) Could be true EXCEPTLeave questions like 20 to the end; the additionalwork you do on the other questions will help youspeed through this otherwise difficult question.We’ve already seen, in question 19, H and kchosen together (B) as well as l and n (D). Inquestion 21 we’ll see F chosen with G (A); andquestion 21’s if-clause tells us that (E) is possible.So if we were to postpone question 20 until later,and use all the scratchwork that we’d done, wecould quickly toss out all of the choices but (C), thecorrect answer. A closer analysis reveals that (C) isimpossible because picking k requires picking n(Rule Four) and then rejecting T (Rule Two).

21. (B) Must be trueA new sketch should have all three raccoonscircled; we then proceed to the rules and see that nhas to go (Rule Two), meaning that k is out as well(Rule Four’s contrapositive), and hence that H isgone too (Rule Three’s contrapositive). Since weneed a total of six and have reached our quota ofthree rejected animals, all of the rest—F, G, and l—will have to be selected, and (B) is true. The othersare all false.

SECTION II

17

22. (A) Must be trueA new sketch in which T is circled must include ncrossed off (Rule Two), and the contrapositives ofRules Four and Three, respectively, confirm that kand H must be rejected as well. We need six, soeverything else—F, G, l, V, and Z (along with T )—hasto be chosen. (A) mentions a pair of animals weare choosing together.

23. (B) Must be trueIf you look back over all of the scratchwork for theprevious questions, you’ll note that every oneinvolved a mix of all three species, as (B) states.Coincidence? No, provable. If (B) were false, thenwe would be able to make up our group of six usingall of the animals of exactly two species (3 + 3).But which species could be left out?

If the group is all monkeys and all pandas—F G H kl n—then we’ve violated Rule One.

If the group is all monkeys and all raccoons—F G HT V Z—then we’ve violated Rule One again.And if the group is all pandas and all raccoons—k ln T V Z—then we’ve violated Rule Two.That’s how we prove that any group of six mustinclude at least one member of each species, andhence that (B) must be true.

(A) is similar but different. Question 21’s if-clausealone tells us that all three of at least one type ofanimal, raccoons, can be selected.

(C)—only one panda was chosen in question 21.

(D)—in question 19, the group H k l n V Z waspossible, and that contains one monkey, not two.

(E), like (A), is disproved by question 21’s “If”clause.

PREPTEST 40 EXPLAINED

18

SECTION IIILOGICAL REASONING

1. (B) Paradox

To resolve a paradox or “apparent discrepancy,”you need a new fact that makes the two givenfacts consistent.

Many big-budget films rack up huge grosses, and soyou’d think that they—and not the low-budget ones—would be the biggest overall contributor to the overallrevenue pool. But if low-budgeters outnumber big-budgeters by a considerable margin, as (B) says,then it’s small wonder that in the aggregate, it’s thelow-budgeters that make the most money.

(A) brings up recouped production costs, which areno part of total gross revenue, and a “need” to selltickets doesn’t mean that people have to buy them.

(C) lumps all revenues together in its comparisonto previous years, so it can’t work out thediscrepancy between the two types of movies.

(D), like (A), hinges on the irrelevant issue ofcosts. The scope of the argument is grossrevenues, not profits.

(E) is yet another irrelevant appeal to cost. Also, wecannot be sure that low-budget movies arecompleted in more or less time than big-budgetones.

2. (C) Strengthen/All EXCEPT

When four choices strengthen an argument, itfollows that the right answer either weakens thatargument, or lies outside the scope and hence hasno effect on the argument.

Dr. Pagano believes that the cause of thisbutterfly’s northward shift is due to climaticchange, on the basis of the correlation betweenthat shift and the northward shift of warm zones.Correlation is not causation, of course, so the fourchoices will have to add some causality to Dr.Pagano’s thesis.

(A) supports the causality by asserting thebutterflies’ sensitivity to temperature in the firstplace.

(B) does so indirectly, by asserting that thebutterflies themselves aren’t affected by warmthbut the plants they depend on are.

(C) actually weakens the argument and thus is theright answer. If the butterflies readily adapt to

climatic change, then it’s likely that (contrary to Dr.P.) something other than climate is causing them tomove north.

(D) supports cause-and-effect in the other direction.If the cold reduces the butterfly population, thenthat supports the idea that climate does indeedinfluence butterfly behavior. (D) doesn’t prove Dr.P’s thesis, but then strengtheners are neverrequired to do so; they just have to make the thesismore likely.

(E)—“Only in warm climates” means that warmth isa necessary condition for the species closelyrelated to the checkerspots, and thus thecheckerspots are likely to depend on warmth aswell.

3. (C) Inference

“Inference” means “must be true”—the rightanswer has a high truth threshold.

No argument from the Professor, just someassertions: Great authors, while “the best users ofa language,” have less respect for correct grammarand style than the rest of us. In fact the authorsays “than most of us,” which supports (C): Themajority of people, as (C) says, use properlanguage more often than the “best users,” the“talented” users, those who use language in a way-out way.

(A)—no career advice for writers can be taken fromthe Professor’s mere observations on who tends touse language properly vs. originally.

(B) is too downbeat in its suggestion that there’s a“risk” in developing an idiosyncratic style—theProfessor calls that a mark of greatness. Also, theProfessor doesn’t suggest (B)’s alleged cause-and-effect: that bad grammar somehow causes a wackystyle.

(D)—no criticism, on the Professor’s part or anyoneelse’s, is implied.

(E)—setting standards is way beyond the scope ofthese simple assertions about style vs. propergrammar.

4. (A) Inference (Conclusion)

The author’s main conclusion is usually statedexplicitly.

“For” (line 5) is a synonym for “because,” and thelast clause is therefore the evidence for the second

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clause, which (A) paraphrases. Notwithstanding ouroccasional ability to predict human behavior, to doso doesn’t mean that we understand it (conclusion)because one needs to know the goal of humanbehavior (evidence), something that the authorimplies we can never know.

(B) contradicts the author. He explicitly states thatprediction can and does exist independent ofunderstanding of purpose.

(C)—the author never tells us what understandingconsists of (or “in,” in the test makers’ odd usage),only what it requires. In other words, the authorprovides a condition necessary for understandingbut not—as (C) suggests—the conditions sufficientfor it.

(D) reflects sentence 1, which mentions theprediction of physical behavior in order to draw acontrast with the prediction of human behavior(from which the author proceeds to his trueinterest, the understanding of human behavior).

(E)—“psychological states” is jargon, mumbo-jumbothat doesn’t appear in the text and certainlydoesn’t amount to a paraphrase of “knowing ahuman actor’s goal.”

5. (B) Weaken the Argument

Watch for examples of mistaking sufficiency fornecessity, and vice versa.

Harvesting grain is sufficient for scratching sickleblades, we know that. But that doesn’t mean thatthat’s the only way in which the blades could bescratched—in other words, harvesting isn’tnecessary for the scratches. By proposing analternative explanation for the scratches on site#1’s blades, (B) undermines the author’s certaintythat site #1’s blades were used in harvesting.

(A)—a mix of scratched and unscratched blades atsite #1 wouldn’t weaken the conclusion that thesite’s scratches were the result of harvesting:Whatever scratches were there would still speak forthemselves, at least in the author’s faultyreasoning.

(C)—any alternative use for blades is irrelevant tothis argument unless such use results in scratches,and (C) gives no reason to believe that the ritualswould do so.

(D) actually strengthens the argument, by assertingthat harvesting did take place at site #2, althoughwith the aid of tools other than sickles—just as theauthor said.

(E) focuses on the manufacture of the sicklesrather than their use. Irrespective of who madethem, how were they used? That’s the centralquestion.

6. (E) Method of Argument (Role of a Claim)

A conclusion is the sentence that makes you ask“Why? How so?”—and that the rest of theargument serves to support.

The statement in question is sentence 1, and if youwere to ask the author “How so? What do youmean?,” he’d use the rest of the stimulus, theWWII example, to answer you. This makes the firstsentence the conclusion, and (E) is therefore thestraightforwardly correct answer.

(A)—assumptions are by definition unstated, butthis question deals with the role of an explicitsentence. No statement in the text can ever be anassumption!

(B) and (C) are 180s. As the main conclusion,sentence 1 can hardly undermine itself (B) ordiscredit itself (C).

(D)—when a speaker “takes a statement forgranted” it means she provides no support for it.But sentences 2 and 3 are clearly support forsentence 1 (and sentence 4 restates it in moreexplicit terms). So (D) is just not accurate.

7. (C) Paradox / All EXCEPT

If the four wrong choices all resolve a paradox, itfollows that the right answer must either deepenthe paradox or be irrelevant to it.

The author seems puzzled that cold fusion wouldonly reduce our electric bills a measly 25%, givenits “virtually unlimited” supply from cheap rawmaterials. It’s only a puzzle if there’s a directcause-and-effect relationship between those twofacts. Attack the choices, confident that four ofthem will throw a wrench into that relationship.

(A)—many students jumped at this one on thegrounds that generator building costs are one-timeand fixed. Maybe so, but maintenance costs aren’t.The greater, ongoing maintenance expenses of coldfusion would surely explain why more savingswouldn’t be passed on to the consumer.

(B), in the same way, explains an increased cost ofdoing business (more expensive regulation) thatwould plausibly eat up some of the consumers’savings.

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(C) is irrelevant to the paradox, which concernsonly those electric companies—however few ormany—who did choose to switch over to coldfusion. Whether many would go along as (C) says,or whether they’d balk, makes no difference.

(D) attacks the cause-and-effect relationship in adifferent way from (A) and (B), but succeedsnonetheless. (D) implies that the author should not,in the first place, be comparing the cheap supply ofcold-fusion energy with the savings on the bill,because the latter has little to do with the former.

(E) is subtler still. But if personnel costs—whichcould be quite high—have nothing to do with theraw materials, then those costs could clearly eat upthe savings that would otherwise show up on theconsumer’s bill. So (E), too, serves to resolve theseeming contradiction.

8. (D) Strengthen the Argument

A strengthener need not prove the conclusion—indeed it rarely does so. Instead, it makes theconclusion more likely to follow from the evidence.

The conclusion (“It is evident, therefore…”) is arecommendation that there should be more reptheaters. Each piece of evidence has little to dowith the others—actors, stagehands, and managershave very different reasons to applaud reptheater—so strengthening any one will strengthen itall. This one is hard to predict; let’s consider themas you probably did: in order.

(A)—the need for a large capital outlay would likelysuit the actors and stagehands, if not themanagers; but if anything it would seem to be adisadvantage to instituting a rep system.

(B)—how can the patrons’ need “to pay overlyclose attention” to a schedule redound to theadvantage of a repertory theater?

(C)—like the previous two choices, (C) presents adisadvantage—or at least an inconvenience—associated with a rep theater.

(D)—theater managers like rep theater because bigrevenues can accrue if—big if—you can giveaudiences what they like. The flexibility that (D)describes would make that “if” more likely, andhence tends to strengthen the argument for a repsetup. (D) is the winner.

(E) would certainly work against the success of arepertory arrangement (conversely, a statement thatactors have no trouble switching from role to rolewould support such a plan).

9. (C) Principle

A principle (or inference) often stays quite closeto the language of the text.

“Note to self: Collaborate with someone on nextbook to ensure sales.” How come? Because herfirst book sold so well thanks to such acollaboration. (C) fairly explicitly echoes thatreasoning and her hopes.

(A) departs from the author’s logic because of itsfinal if-condition. The writer isn’t necessarilyplanning to use the same collaborator, just acollaborator.

(B) is a popular wrong answer, but popularity doesnot equate to acceptability. The writer believes thatwriting with a collaborator is sufficient to ensuregood sales—which is why she wants to do it again.(B)’s assertion that collaboration is necessarydoes nothing to support the logic.

(D) commits the common fallacy of denying the “if”and “then” terms. To prove (D)’s assertion that “nocollaborator weak sales” has no effect on thewriter’s belief that “collaborator strongsales.” This is a common mistake made to trapstudents who aren’t paying attention. Rememberthat you form the contrapositive to an if-then bynegating each element and flipping around thearrow.

(E), like (A), adds an extraneous condition (thequality of the writer’s work, in this case) and thuscannot support or justify the writer’s logic.

10. (B) Logical Flaw

When seeking a logical flaw within a chain oflogic, look for mismatched terms.

At the end of this chain of “illogic,” the authorconcludes (“Thus…”) that whenever a kid has alearning deficit, it’s because of a malfunctioninghippocampus. But nowhere in the argument does theauthor discuss learning deficits in general; he talksabout short-term memory defects and attributesthem to a faulty hippocampus, but that’s a verydifferent, limited issue. Because the broad categoryof learning deficits can include many more deficitsthan just that one, (B) precisely points to the flaw.

(A)—the problem is that the author generalizesfrom one specific deficit to deficits in general, butthat’s not a matter of a “too-small sample.”

(C) misstates—reverses, actually—the author’sfirst sentence, so for once it’s the answer choice

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that commits the logical flaw. The author statesthat if a short-term memory deficit is present, thecause is the hippocampus malfunctioning, whereas(C) accuses the author of assuming that allmalfunctioning hippocampuses (hippocampi?) causememory deficits.

(D)—since the conclusion is, as we’ve noted, aboutlearning deficits in general, “only a few moments”is perfectly adequate as a quantification of the timeinvolved in short-term memory.

(E) draws an irrelevant comparison between adultand child learning. The author has no interest indistinguishing between them.

11. (E) Inference

Don’t work at predicting an answer to an LSATInference question. Just understand the stimulusand then proceed to the choices.

The historian’s comments almost amount to anLSAT-style paradox. It’s agreed that adults raisedunder the practice of punishing a child by sittinghim alone outdoors showed no less confidence thanadults not so raised—this, despite the feelingamong child psychologists that that punishmentcauses damage to self-esteem, which in turn leadsto less confidence. Let’s go through the choices asyou doubtless did, in order, looking for that whichmust be true based on this text.

(A) goes too far. The author stops short of drawingthe categorical conclusion that the childpsychologists are wrong.

(B)—the last sentence talks about average levelsof confidence, not (as (B) does) the extremes.

(C) distorts a most tangential aspect of theparagraph, namely the passersby observing apunished child. That it’s tangential doesn’t make(C) wrong; it’s just that the author is concernedwith the effects of the punishment, not its meaningto observers.

(D) commits the classic error of negating an if-thens terms without flipping the terms. That lowerself-esteem leads to less confidence doesn’t meanthat high self-esteem leads to high confidence. Thecorrect formulation would be: “NOT less confidenceleads to NOT lower self-esteem.”

(E) is all that’s left, and its conditional naturemakes it easier to accept as true than the others. Itdistinguishes between the general tendency (oflower self-esteem leading to lower adult confidence)and the particular behavior, which (E) properly cites

as an exception to that tendency. (E) readily followsfrom the text.

12. (E) Logical Flaw

One of the most common logical flaws on the LSATis unexamined alternatives (see also question 14).

The novelist writes off grammar books as useless forwriters, because writers won’t seek to consult themwhether they think a sentence is ungrammatical (inwhich case they won’t write it) or know it isgrammatical. But he fails to consider the vast middleground of possibilities between those two extremes:the situations in which a writer might just not be sureas to the correctness of a sentence he had plannedor written; situations in which a grammar book mightbe just the ticket. (E) alludes to those cases.

(A) thinks that the conclusion is that writers won’tuse grammar books, when it’s simply that theydon’t need them.

(B)—an author’s sureness about the correctgrammar of his sentence is not contingent on hismistake about some other sentence’s correctness,at least insofar as the novelist constructs hisargument. This one really makes a hash of thephrases in the paragraph.

(C)—non-authors are outside the scope, so thenovelist may or may not find grammar books usefulfor them.

(D)—uses for a grammar book other than as areference source (as a doorstop? As a coaster?)are outside the scope of the argument.

13. (E) Method of Argument

When answer choices are written in a highlyabstract fashion, be rigorous in applying theargument’s terms to the choices. Otherwise they’llall sound tempting.

Sentence 4 spells out the certainty alluded to insentence 2—that Britain’s rabies-free status mustcome to an end. Airborne European bats will takecare of that, notwithstanding the quarantine policy.(E) expresses, in formal terms, exactly what theauthor says: A policy (the quarantine) must fail(“cannot succeed indefinitely”) because a likelysource of defeat (the flying bats) fall outside thepolicy itself.

(A)—the “other factors” (the flying bats) will workagainst the current results of the policy. This isreally a 180.

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(B)—the objection to the quarantine policy (thatbats can fly into Britain unquarantined) is hardly“irrelevant” to it, since it foredooms the policy inthe long run.

(C)—no dereliction of duty is stated or implied. It’snot the officials’ fault that flying bats can’t bestopped by a quarantine.

(D)—the quarantine is universally adopted inBritain, and Britain is the “universe” of theargument’s scope, so (D) is way off.

14. (A) Logical Flaw

When attacking a Logical Flaw question, you can’tgo wrong if you ask yourself, “What possibility isthis author unaware of?”

Why does Franklin give Miller a pass? Because herhandwriting doesn’t match the note involved in thepractical joke. But couldn’t Miller have gottensomeone else to write it? If so, then Miller is thejoker—or one of them. That the joke could have twopranksters is what Franklin misses but that (A)understands.

(B) splits hairs on the handwriting. But Franklin issure that it isn’t Miller’s, and in any case only onehandwriting sample is discussed.

(C) is factually false. Miller’s past jealousy isexplanation enough.

(D)—Franklin’s reasoning requires no more than onepiece of evidence, since that piece of evidence is thepractical joke. If the joke involves no other evidence,how could Franklin possibly obtain more?

(E)—that Franklin is convinced that Miller isn’t theculprit because it’s not her handwriting, doesn’timply that Miller would be the culprit if herhandwriting matched. These are two separate anddiffering assertions.

15. (E) Assumption

An assumption must be true in order for theevidence to lead to the conclusion.

The conclusion (“As a result…”) that companiesrarely hire liberal arts Ph.D.’s is based on theauthor’s feeling that what interests the Ph.D.’s,namely improved intellect, is diametrically opposedto what interests the companies, namely thecapacity to earn big bucks in business. If there’s nocontradiction between those two things, of course,then by the author’s own logic it would be smart for

companies to recruit Ph.D.’s. So the argumenthinges on there being a firewall between the desireto improve intellect and the desire to makebusiness bucks, and (E) provides it.

(A) is necessity v. sufficiency again. The argumentclaims that the desire to earn big bucks is anecessary condition for getting hired, and thatPh.D.s’ lacking that desire is what makes theiremployment chances so bleak. That’s not to say, as(A) does, that having that desire would besufficient to land a job.

(B) is pretty much stated verbatim in the argument,so it’s not an unstated, missing assumption.Remember, assumptions are always unstated.

(C)—this argument’s scope is the sorryemployment prospects for liberal arts Ph.D.’s. Thatothers might share their alleged disdain for earningis not relevant here.

(D) is tempting, but the argument doesn’t hinge onPh.D.’s wanting to get hired. It’s in the vein of “Ifthey were to seek a job, they wouldn’t get onebecause…” etc. The logic still holds even if few, orno, Ph.D.’s seek employment.

16. (E) Inference (Point at Issue)

If the right answer is a point of disagreement, thefour wrong choices must be points of real, or atleast potential, agreement.

Logan’s point (that old newspapers are useless tothe historian) is followed by Mendez’s “But”:but they tell us a lot about what people thought andfelt years ago. This means that Mendez must beseeing at least some value in old newspapers forthose looking back, making (E) the point ofcontention. Logan explicitly expresses, and Mendezimplicitly denies, (E)’s assertion.

(A)—neither person mentions accuracy, and eachstatement could be read as conceding the accuracyof newspaper reporting .

(B)—“The conventions of newspaper reporting” isnever mentioned, and is so broad a term that onecan imagine both speakers easily agreeing on thispoint.

(C)—since Logan dismisses “ephemeral matters”(if that phrase is equivalent to “popular art”), andsince Mendez sets popular art apart from thatwhich is valuable about newspapers, it’s quitepossible that both would agree that (C) is false.

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(D)—Logan’s beef is with old newspapers, notpresent ones, so (D) wanders way beyond thescope of Logan’s remarks. And while Mendezseems happy with newspapers in general, he mightor might not agree with (D)’s prescription.

17. (A) Parallel Reasoning

Be on the lookout for the two most commonformal logic flaws: reversing the terms (withoutnegating them), and negating the terms (withoutreversing them).

The original—and you’ll see this if you’re lookingout for the most common flaws—makes themistake of reversing the terms of an if-thenstatement. The stimulus essentially goes: “If you’venever been pushed to do more than you can, thenyou’re a person who hasn’t done all you’re capableof. Since Alex hasn’t done all he’s capable of, thenhe’s never been pushed.” The problem is that theexplanation for Alex’s having fallen short of hiscapability may be a lack of pushing, as the authorbelieves, but could lie elsewhere. (Maybe peoplehave pushed him but he’s lazy, or just unlucky.)Putting it simply: We may not reverse the terms ofan if-then statement unless we also negate them.

(A) does so in the same way as the stimulus, andis thus correct. Alicia’s knowledge of the true valueof companionship could be explained by her havinga dog, but perhaps she has a cat or bird or fishtank instead. (Or perhaps she learned it through herinteractions with humans; who knows?) So (A)’sconclusion, like the stimulus’s, need not be true,and for the same reason.

(B) commits the other common flaw—negating theterms of an if-then statement. “If X then Y; sincenot X, therefore not Y.” That’s (B)’s form. It’s poorlogic, but it’s not poor for the same reason as thestimulus, or (A).

(C) demonstrates proper, not flawed, logic. Itconsists of an if-then statement and itscontrapositive: “If not challenged, then noaccomplishment. Since accomplished, thenchallenged.”

(D), too, is proper logic, and even morestraightforwardly: “If it’s a closed plane figurebounded by straight lines, then it’s a polygon. Sincethis object meets that definition, it’s a polygon.”Quite so.

(E) might seem close to the stimulus but deviatesin two significant ways. (E)’s qualifier about Jon

(that he’s lax “when he can afford to lose it”) hasno parallel in the stimulus, and its final clause“must never have lost anything” is substantiallydifferent from “must never have lost somethingthey can’t afford to lose.” Parallel logic is aboutparallel form, and (E)’s form is way off.

18. (B) Strengthen the Argument

To get a grip on an argument, reduce it to simpler(though accurate) terms.

The author reports that playwrights and historians areat cross purposes. The former want a play to produceempathy for the main character, while the latter wanta play to shed light on the society in which it waswritten and don’t feel that these two goals cancoexist. (B) explains why historians might feel thatway—their sense that an accurate view of a society isusually sacrificed for the sake of drama.

(A) raises a comparison between societal portraitsthat isn’t part of the historians’ concern.

(C) and (D) are both 180s; each describes exactlywhat historians believe plays don’t offer.

(D) draws a distinction between popular andunpopular plays that doesn’t appear in thestimulus.

19. (D) Logical Flaw / All EXCEPT

When the four wrong choices are flaws, look for anoutside-the-scope right answer.

So Benton is the best bait for trout fishers, eh?Well, four out of five choices claim that thatconclusion isn’t adequately supported by theevidence—the experiment run by the research firm.(D) is the odd man out because the possibility ofequally effective top brands has no impact on theproven superiority of Benton—“proven,” that is, if theexperiment was on the up and up. The other fourchoices explain why the evidence is actually fishy:

(A)—the experiment only compared five top sellingbaits. A sixth one, or any number of others, couldreadily work better than Benton, contrary to theconclusion. Thus (A) points to a scope shiftbetween best selling and best.

(B)—the conclusion claims that Benton works bestfor “anyone” going trout fishing, a claim notadequately supported by an experiment involvingonly the very best angle