Math Word Problems Demystified - A Self Teaching Guide

(a) There are 8 outcomes in the sample space and one way to get all

boys: BBB; hence,P(all boys)¼^18.

(b) There are 8 outcomes in the sample space and two ways to get

all boys or all girls: BBB and GGG; hence,P(all boys or all

girls)¼^28 ¼^14.

(c) There are 8 outcomes in the sample space and three ways to get

two boys and a girl: BBG, BGB, GBB: henceP(exactly 2 boys

and 1 girl)¼^38.

5. There are 36 outcomes in the sample space and six ways to get a 7
   and two ways to get an 11; hence,P(7 or 11)¼^636 þ^2 ¼ 368 ¼^29.


6. There are 8þ 4 ¼12 cans in the cooler and 4 of them are ginger ale;
   henceP(ginger ale)¼ 124 ¼^13.


7. There are 3þ 5 þ 4 þ 4 ¼16 Popsicles in the box and 4 are grape;
   hence,P(grape)¼ 164 ¼^14.


8. There are 50 tickets and you have 5, so the probability of winning is
   5
   50 ¼

1

10.

9. There are a total of 87þ 49 ¼136 students and 87 are girls; hence,
   P(girl)¼ 13687.


10. There are 50 states and 8 of them begin with the letter M: Maine,
    Maryland, Massachusetts, Michigan, Minnesota, Mississippi,
    Missouri, and Montana. Hence,P(state that begins with M)¼ 508 ¼ 254.

LESSON 22 Word Problems in Probability 275