833.33% is the change from 30 to 280
Calculation steps:
[( 280 - 30 ) ÷ 30] x 100 = 833.33%
Formula
Percentage change = [(280 - 30) / 30] x 100
Subtract the new number by the original number
280 - 30 = 250
250 ÷ 30 = 8.333333333333334
8.333333333333334 x 100 = 833.33%