Question

80​% of what number is 20​?

Answer 1

Let x = the number 

80% * x = 20 
80 / 100 * x = 20 
x = 20 * 100 / 80 
x = 2000 / 80 
x = 25

Answer 2

80/100x=20
or,4/5x=20
or,x=25