30.61% is the change from 490 to 640
Calculation steps:
[( 640 - 490 ) ÷ 490] x 100 = 30.61%
Formula
Percentage change = [(640 - 490) / 490] x 100
Subtract the new number by the original number
640 - 490 = 150
150 ÷ 490 = 0.30612244897959184
0.30612244897959184 x 100 = 30.61%