Page 223 - Basic College Mathematics with Early Integers

200 C HAPTE R 3 I FRACTIONS

Objective Multiplying and Dividing with Fractional
Replacement Values

7 1
PRACTICE 13 Example 13 If x = and y =- , evaluate (a) xy and (b) x , y.
8 3
3 9
If x =- and y = , evaluate 7 1
4 2 Solution: Replace x with and y with - .
(a) xy, and (b) x , y. 8 3
7 1 7 1
a. xy = # - b. x , y = , -
8 3 8 3
#
7 1 7 3
=- = # -
#
8 3 8 1
#
7 7 3
=- =-
#
24 8 1
21
=-
8
Work Practice 13

Objective Solving Problems by Multiplying Fractions

“of” usually To solve real-life problems that involve multiplying fractions, we use our four
translates to multiplication. problem-solving steps from Chapter 1. In Example 14, a new key word that implies
multiplication is used.That key word is “of.”

PRACTICE 14 Example 14 Finding the Number
Hershey Park is an amusement of Roller Coasters in
park in Hershey, Pennsylvania. an Amusement Park
1
Of its 60 rides, of them are Cedar Point is an amusement park located in
6
roller coasters. How many Sandusky, Ohio. Its collection of 68 rides is the
4
roller coasters are in Hershey largest in the world. Of the rides, are roller
Park? 17
coasters. How many roller coasters are in Cedar
Point’s collection of rides? (Source: Wikipedia)

Solution:
1. UNDERSTAND the problem. To do so, read and reread the problem. We are
4
told that of Cedar Point’s rides are roller coasters. The word “of” here
17
means multiplication.

2. TRANSLATE.
number of 4 total rides at
In words: is of
roller coasters 17 Cedar Point
T T T T T Copyright 2012 Pearson Education, Inc.
Answers number of 4
Translate: = # 68
27 1 roller coasters
13. a. - b. - 17
8 6
14. 10 roller coasters