How do you solve the following problems that involve percentages?

5 is 20% of what number?

20% of 120 equals ?

5 is what percent 25?

In each of these problems you can use the formula,

is/of =%/100

solving percentage problems

Let’s see how this works.

5 is 20% of what Number?

5/x = 20/100

Cross multiply

20x = 500

Divide by 20

x = 25

 

What is 20% of 120 ?

x/120 = 20/100

Cross multiply

100x = 2400

Divide both sides by 100

X = 24

 

5 is what percent of 25?

5/25 = x/100

Cross Multiply

25x =500

Divide both sides by 25

x = 20




This video works several similar problems. Each problem can be solved using is over of.