400% is the change from 15 to 75
Calculation steps:
[( 75 - 15 ) ÷ 15] x 100 = 400%
Formula
Percentage change = [(75 - 15) / 15] x 100
Subtract the new number by the original number
75 - 15 = 60
60 ÷ 15 = 4
4 x 100 = 400%
Example