Zack had 20 people show up to his first exercise class. He had 36 come to his second class. what is the percent increase?

Find the difference between two classes

difference = 36 - 20

difference = 16

Transform the difference to percentage form

percentage = difference/beginning class

percentage = 16/20

Percentage is per hundred, so we should change the denominator to 100, multiply it by 5

percentage = 16/20

percentage = (16 * 5) / (20 * 5)

percentage = 80/100

percentage = 80%

The answer is 80%

Percentage increase = (36-20) / 20 = 80%