Page 337 - Basic College Mathematics with Early Integers

314 C HAPTE R 4 I DECIMALS

Objective Using Decimals as Replacement Values

PRACTICE 10 Example 10 Evaluate x , y for x = 2.5 and y = 0.05.
Evaluate x , y for x = 0.035
and y = 0.02. Solution: Replace x with 2.5 and y with 0.05.
50
x , y = 2.5 , 0.05 0.052.5 becomes 5250
= 50
Work Practice 10

Objective Solving Problems by Dividing Decimals

Many real-life problems involve dividing decimals.

PRACTICE 11 Example 11 Calculating Materials Needed for a Job

A bag of fertilizer covers
1250 square feet of lawn.Tim A gallon of paint covers a 250-square-foot area. If Betty Adkins wishes to paint a
Parker’s lawn measures 14,800 wall that measures 1450 square feet, how many gallons of paint does she need? If
square feet. How many bags of she can buy only gallon containers of paint, how many gallon containers does she
fertilizer does he need? If he need?
can buy only whole bags of Solution:
fertilizer, how many whole bags 1. UNDERSTAND. Read and reread the problem. We need to know how many
does he need?
250s are in 1450, so we divide.
2. TRANSLATE.

number of square divided square feet
In words: is
gallons feet by per gallon
T T T T T
number
Translate: = 1450 , 250
of gallons
3. SOLVE. Let’s see if our answer is reasonable by estimating.The dividend 1450
rounds to 1500 and the divisor 250 rounds to 300.Then 1500 , 300 = 5.
5.8
2501450.0
- 1250
200 0
- 200 0
0
4. INTERPRET. Check your work. Since our estimate is close to our answer of 5,
our answer is reasonable. State your conclusion: Betty needs 5.8 gallons of
paint. If she can buy only gallon containers of paint, she needs 6 gallon contain-
ers of paint to complete the job.

Work Practice 11
Copyright 2012 Pearson Education, Inc.

Answers
10. 1.75
11. 11.84 bags; 12 bags