240% is the change from 90 to 306
Calculation steps:
[( 306 - 90 ) ÷ 90] x 100 = 240%
Formula
Percentage change = [(306 - 90) / 90] x 100
Subtract the new number by the original number
306 - 90 = 216
216 ÷ 90 = 2.4
2.4 x 100 = 240%
Example