WORD PROBLEMS

Beth Marengo

JSerra Catholic High School

Math Department

Overview: 6 Step ProcessOverview: 6 Step Process Step 1: What does the problem ask you to

find? Step 2: Let Statement Step 3: What do you know? Step 4: Algebraic Equation and Solution Step 5: Check your answer Step 6: Write a Sentence

Example Problem

A chemist has 10 milliliters of a solution that contains a 30% concentration of

acid. How many milliliters of pure acid must be added in order to increase the

concentration to 50% ?

STEP 1: What does the problem

ask you to find?

A chemist has 10 milliliters of a solution that contains a 30% concentration of acid. How many milliliters of pure acid must be added in order to increase the concentration to 50% ?

The question is: What amount of pure acid should the chemist

add?

Step 2: Let Statement

This is the step where you identify your variable. Your variable should always refer to the unknown amounts from Step 1.

Let x = amount of pure acid to be added.

Step 3: What do you know? Students should do one of the following

Draw a picture Write a verbal equation

+ =Amount: 10 ml x ml 10 +x ml

Concentration: 30% 100% 50%

Step 4: Equation/SolutionTake what you know from your picture/verbal

equation and transform into an algebraic equation

.30(10) + 1.00(x) = .50(10 + x) 3 + x = 5 + .5 x

.5x = 2 x = 4

+ =

10 ml (30%) x ml (100%) 10 +x ml (50%)

Step 5:Check Answer

Ask the students, does your answer sound reasonable? For example if we had reached a negative

solution, this is not reasonable. You cannot add a negative amount of milliliters to increase concentration.

Students tend to overlook the fact that these are real life problems and require real life solutions.

Step 6:Write Sentence

Put your answer into a complete sentence. This accomplishes two very important things.

Double checks that the answer is reasonable. Ensures that you answered the question being asked.

THE CHEMIST NEEDS TO ADD 4 MILLILITERS OF PURE ACID TO THE

SOLUTION.

Thank You and Questions

ANY SUGGESTIONS? QUESTIONS?