Pre-Algebra Demystified

Solve the equation for x:

0 : 42  500 ¼x

210 ¼x

(Be sure to change the percent to a decimal before multiplying.)

EXAMPLE

15 is what percent of 60?

SOLUTION

what

15 is percent of 60?

## # ##

15 ¼ x  60

15

60

¼

x 60

60

0 : 25 ¼x

25 %¼x

EXAMPLE

90% of what number is 36?

SOLUTION

90% of what number is 36?

#####

90 %  x ¼ 36

0 :90x¼ 36

0 : 90 x

0 : 90

¼

36

0 : 90

x¼ 40

PRACTICE

Solve each percent problem using an equation:

1. 54% of 105 is what number?


2. 72% of what number is 360?


3. 55 is what percent of 440?


4. 6% of 88 is what number?


5. 35 is what percent of 350?

148 CHAPTER 7 Expression and Equations