5120% is the change from 15 to 783
Calculation steps:
[( 783 - 15 ) ÷ 15] x 100 = 5120%
Formula
Percentage change = [(783 - 15) / 15] x 100
Subtract the new number by the original number
783 - 15 = 768
768 ÷ 15 = 51.2
51.2 x 100 = 5120%
Example