4000% is the change from 15 to 615
Calculation steps:
[( 615 - 15 ) ÷ 15] x 100 = 4000%
Formula
Percentage change = [(615 - 15) / 15] x 100
Subtract the new number by the original number
615 - 15 = 600
600 ÷ 15 = 40
40 x 100 = 4000%
Example