6th Grade Math Textbook, Fundamentals

 &KDSWHU

7-5

Find a Percent

Objective To find what percent one number is of another using the percent

formula or a percent proportion

A research group sent out questionnaires to
determine how many hours teenagers typically
spend each week playing electronic games. Of the
500 questionnaires sent out, 350 were answered
and returned. What percent of the questionnaires
sent out were answered and returned?

To find the percent, find what percent 350 is of 500.

Here are two ways to find the percent

one number is of another:

Remember:

Percent Formula

r• b p

rate (r) • base (b) percentage (p)

Both methods show that 70% of the questionnaires sent out

were answered and returned.

0% ?%

0 350 500

100%

Method 1 Use the Percent Formula

r • bp

r • 500  350

 Divide both sides by 500 to isolate r.

 Simplify.

r 10070 70%

350

500

70

100

r• 500

500

350

500

r• 500

500

Substitute 350 for the percentage, p,

and 500 for the base, b.

Method 2 Use a Percent Proportion

Let nrepresent the unknown percent.

Solve: 

350 • 100  500 n Cross multiply.

 Divide both sides by 500 to isolate n.

 Simplify.

70 n

So 70%.

Check: Substitute 70 for n, and cross multiply.

35,000 35,000 Tr u e

500 n

500

350 • 100

500

500

500

1

1

n

70

100

?

(^350500) 
70
100
n
100
350 100
500
70 1
(^51)

Substitute 350 for the percentage, p,

and 500 for the base, b.

n

100

350

500

Remember:

Percent Proportion



percent (%)

100

percentage (p)

base (b)

part

whole

percentage

(returned

questionnaires)

base

(total

questionnaires)

percent

(unknown)