10.71% is the change from 280 to 310
Calculation steps:
[( 310 - 280 ) ÷ 280] x 100 = 10.71%
Formula
Percentage change = [(310 - 280) / 280] x 100
Subtract the new number by the original number
310 - 280 = 30
30 ÷ 280 = 0.10714285714285714
0.10714285714285714 x 100 = 10.71%