Page 222 - Algebra 1

Example
4
Calculating Odds
A bag contains 6 red marbles, 2 yellow marbles, and 1 blue marble.
a. What are the odds of drawing a red marble?
SOLUTION
Look at the favorable outcomes and the unfavorable outcomes. There are 6 red marbles (favorable outcomes).
There are 3 marbles that are not red (unfavorable outcomes). The odds of drawing a red marble are 6:3 or 2:1.
b. What are the odds against drawing a blue marble? SOLUTION
Look at the favorable and the unfavorable outcomes.
There are 8 marbles that are not blue (unfavorable outcome). There is 1 blue marble (favorable outcome).
The odds against drawing a blue marble are 8:1.
Solving Multi-Step Problems Involving Probability
Isaac has 6 blue and 4 white shirts in his closet. There are also 2 pairs of navy pants and 3 pairs of khaki pants in his closet.
a. What is the probability Isaac will choose khaki pants and a white shirt from his closet?
SOLUTION
P(khaki pants) = _3 5
P(white shirt) = _4 = _2 10 5
P(khaki pants and white shirt) = _3 · _2 = _6 5 5 25
b. Assume that after the pants and shirt are worn, they are put in the laundry hamper. What is the probability that he will choose khaki pants and a white shirt from the closet to wear the next day?
SOLUTION
P(khaki pants) = _2 = _1 42
P(white shirt) = _3 = _1 93
P(khaki pants and white shirt) = _1 · _1 = _1 236
Hint
The sum of the favorable and unfavorable outcomes should be
the same as the total possible outcomes.
Example
5
Lesson 33 207