Solving Percentage Problems

Solving Percent Problems

To solve a percent problem, remember to use a percent proportion!

 $\frac{is}{of}=\frac{\%}{100}$  

First, you have to identify each part of the question.

What is the part (is), what is the whole (of), and what is the percent (%).

20 is what percent of 32?

• What number represents the part (is)? 20

• What number represents the whole (of)? 32

• What number represents the percent (%)? Since we do not know the percent, we will replace it with a variable.

Now fill in your proportion.

 $\frac{20}{32}=\frac{x}{100}$  

Now use CSI to solve.

• Cross Multiple 32 times x = 100 x 20

• Simplify 32x = 2000

• Isolate

   $\frac{32x}{32}=\frac{2000}{32}$  

• x = 62.5%

Multiple Choice

Now you try!

18 is what percent of 24?

• 50%

• 65%

• 70%

• 75%

Multiple Choice

15% of 62 is what number?

• 9

• 9.3

• 9.8

• 10

Multiple Choice

What is 7% of 45?

• 31.5

• 35

• 41

• 55

Multiple Choice

25 is 5% of what number?

• 250

• 500

• 750

• 1000