60% is the change from 15 to 24
Calculation steps:
[( 24 - 15 ) ÷ 15] x 100 = 60%
Formula
Percentage change = [(24 - 15) / 15] x 100
Subtract the new number by the original number
24 - 15 = 9
9 ÷ 15 = 0.6
0.6 x 100 = 60%
Example