I am not a maths wiz so to work out this problem I brake it down into the following steps -

- What is 10% of 130 (this is easier for me to work out, just move the decimal place over to the left by one digit)

130.00, therefor 10% = 13.00

- What is half of the 10% figure, which is technically 5% of 130.

13.00 / 2 = 6.5

- Add the 2 figures together to get the total 15%

13.00 + 6.5 = 19.5

therefor

When I am working with percentages I always brake it down and find out what 10% is first and work the answer out from there. Personally I find it easier. I hope this helps you too.15% of 130 = 19.5