Number pattern 5, 7.5, 11.25, 16.875

Not sure what you are asking but if you are looking for the next 3 numbers then multiply 5 by 1.5, 7.5 by 1.5, and 11.25 by 1.5
5 * 1.5 = 7.5
7.5 * 1.5 = 11.25
11.25 * 1.5 = 16.875
16.875 * 1.5 = 25.3125
25.3125 * 1.5 = 37.96875
37.96875 * 1.5 = 56.953125 

The answer should be 3%

You didn’t put the necessary image to solve the question : p