115.38% is the change from 13 to 28
Calculation steps:
[( 28 - 13 ) ÷ 13] x 100 = 115.38%
Formula
Percentage change = [(28 - 13) / 13] x 100
Subtract the new number by the original number
28 - 13 = 15
15 ÷ 13 = 1.1538461538461537
1.1538461538461537 x 100 = 115.38%