Ally raised her math grade from a 75 to a 90. What was the percentage of increase?

Question

I don't understand. In 6th grade btw

Answer 1

Hew, percent of increase or decrease is the difference/the original amount.

 

(90 - 75)/75 = 15/75 = .2 = 20%

 

FYI, if it were the opposite (grade dropped from 90 to 75) and asked for the percent of decrease...

 

(90 - 75)/90 = 15/90 = .17 = 17%