Respuesta :

Let if you earn $100 per hour a raise of 2.5% means you will get $102.5.
i.e 102.5% of earlier.
in case of $6, it will be its 102.5%, = 102.5*6/100 = $6.15 per hour.
The answer to your question is: 

15

Because:

You multiply 2.5 and 6 to each other and get the product of:

15