-46.25% is the change from 400 to 215
Calculation steps:
[( 215 - 400 ) ÷ 400] x 100 = -46.25%
Formula
Percentage change = [(215 - 400) / 400] x 100
Subtract the new number by the original number
215 - 400 = -185
-185 ÷ 400 = -0.4625
-0.4625 x 100 = -46.25%