20 plus 15 percent = 23
4.43 plus 15 percent is 5.0945
23 percent plus 15 percent is 38 percent. However, this only works if the percents are of the same thing.
(15%) + (10%) = 0.25
138.00 + (15%) = 158.70
25 + (15%) = 28.75
14.00 + (15%) = 16.10
48.87
115
16.05
289.8
517.5