400% is the change from 78 to 390
Calculation steps:
[( 390 - 78 ) ÷ 78] x 100 = 400%
Formula
Percentage change = [(390 - 78) / 78] x 100
Subtract the new number by the original number
390 - 78 = 312
312 ÷ 78 = 4
4 x 100 = 400%
Example