Beginning Algebra, 11th Edition

130 CHAPTER 2 Linear Equations and Inequalities in One Variable

OBJECTIVES

Ratio, Proportion, and Percent

2.6

1 Write ratios.

2 Solve proportions.

3 Solve applied

problems by using

proportions.

4 Find percents and

percentages.

OBJECTIVE 1 Write ratios.A ratiois a comparison of two quantities using a

quotient.

Ratio

The ratio of the number ato the number is written

or

a

b

a to b, a:b,.

b 1 where bZ 02

Writing a ratio as a quotient is most common in algebra.

Writing Word Phrases as Ratios

Write a ratio for each word phrase.

(a)5 hr to 3 hr

(b)6 hr to 3 days

First convert 3 days to hours.

Now write the ratio using the common unit of measure, hours.

Write in lowest terms. NOW TRY

An application of ratios is in unit pricing,to see which size of an item offered in

different sizes produces the best price per unit.

Finding Price per Unit

A Cub Foods supermarket charges the following prices for a jar of extra crunchy

peanut butter.

Which size is the best buy? That is,

which size has the lowest unit price?

EXAMPLE 2

6 hr

3 days

=

6 hr

72 hr

=

6

72

=

1

12

3 days= 3 # 24 =72 hr 1 day=24 hr

5 hr

3 hr

=

5

3

EXAMPLE 1

a

b

Size Price

18 oz $1.78

28 oz $2.97

40 oz $3.98

PEANUT BUTTER

NOW TRY
EXERCISE 1
Write a ratio for each word
phrase.

(a)7 in. to 4 in.

(b)45 sec to 2 min

NOW TRY ANSWERS

1. (a)^74 (b)^38

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