680% is the change from 50 to 390
Calculation steps:
[( 390 - 50 ) ÷ 50] x 100 = 680%
Formula
Percentage change = [(390 - 50) / 50] x 100
Subtract the new number by the original number
390 - 50 = 340
340 ÷ 50 = 6.8
6.8 x 100 = 680%
Example