Chapter 15 Lesson 3

Finding OutcomesPages 421-4231-3 all

Cornell Notes – Chap. 15 Lesson 3

Main Ideas/Cues:Disjoint events

Details:Events that have no outcomes in

common.

Example: When rolling a number cube, the events “getting an odd number” and “getting a 4” are disjoint events.

Cornell Notes – Chap. 15 Lesson 3

Main Ideas/Cues:Overlapping events

Details:Events that have one or more outcomes

in common.

Example: When rolling a number cube, the events “getting a number less than 3” and “getting an even number” are overlapping events because they have the outcome 2 in common.

Cornell Notes – Chap. 15 Lesson 3

Main Ideas/Cues:Complementary

events

Details:Two disjoint events such that one or the

other of the events must occur.

Example: When rolling a number cube, the events “getting an odd number” and “getting an even number” are complementary events.

Cornell Notes – Chap. 15 Lesson 3

Problem #1

First Step: Write the Problem

1. Tell whether the events involving the spinner are disjoint or overlapping.Event R: Spin a number divisible by 4.Event S: Spin a prime number

Problem #1

Second Step: List the numbers for each event.

1. Event R: 4 and 8Event S: 2, 3, and 7

Spin a number divisible by 4

Spin a prime number

Problem #1

Third Step: Are any outcomes in common?

1. Event R: 4 and 8Event S: 2, 3, and 7

Disjoint; No outcomes are in common, a prime number is not divisible by any

number other than 1 and itself.

Problem #2

First Step: Write the Problem

2. Malcolm has 2 green tiles, 4 yellow tiles, and 3 blue tiles in a bag. He chooses 1 tile out of the bag without looking. What is the probability that the tile is green or blue?

Problem #2

Second Step: Rewrite using the Probability formula.

2. P(green or blue) = P(green) + P(blue) 2 + 3

9 9 P( ) P( ) Number of green tiles + Number of blue tiles Total number of tiles Total number of tiles

Problem #2

Third Step: Add the fractions.

2. P(green or blue) = P(green) + P(blue)

2 + 3 = 5 9 9 9Answer

Problem #3

First Step: Write the Problem

3. On a subway, 30% of the riders have briefcases. What is the probability that a randomly chosen rider does not have a briefcase? About how many riders out of 350 would not have a briefcase?

Problem #3

Second Step: Change the percent to a decimal and subtract from 1.

3. P(has a briefcase) = 1 – P(does not have a briefcase)

1 – 0.3 = 0.7 ; 70% do not have a briefcaseWhat is the decimal for 30%?

How many do not have a briefcase?

Answer to the first question!

Problem #3

Third Step: Now find 70% of 350. Write the percent equation and replace the variables with the known numbers

3. a = 70% • 350 a = 0.7 • 350 a = 245

245 riders out of 350 would not have a briefcase.

a = p% • b

Answer to the second question!

Change the percent to a decimal

Answer

Cornell Notes Summary

Include the following statement and answer in your Cornell Notes Summary.

How do you find the probability that either event A or event B will occur if they are disjoint events?

You can find the probability that either event A or event B will occur if they are disjoint events by ____________.