312.5% is the change from 24 to 99
Calculation steps:
[( 99 - 24 ) ÷ 24] x 100 = 312.5%
Formula
Percentage change = [(99 - 24) / 24] x 100
Subtract the new number by the original number
99 - 24 = 75
75 ÷ 24 = 3.125
3.125 x 100 = 312.5%
Example