11.5% is the change from 287 to 320
Calculation steps:
[( 320 - 287 ) ÷ 287] x 100 = 11.5%
Formula
Percentage change = [(320 - 287) / 287] x 100
Subtract the new number by the original number
320 - 287 = 33
33 ÷ 287 = 0.11498257839721254
0.11498257839721254 x 100 = 11.5%