107.5% is the change from 400 to 830
Calculation steps:
[( 830 - 400 ) ÷ 400] x 100 = 107.5%
Formula
Percentage change = [(830 - 400) / 400] x 100
Subtract the new number by the original number
830 - 400 = 430
430 ÷ 400 = 1.075
1.075 x 100 = 107.5%
Example