budgeting question

Hi,

It has been a while since I have looked at Budgeting, however I arrive at the correct answer by breaking it down like this.

If the allowance for energy is 5%, then 113400 is equal to 105%

Divide 113400 by 105 and then multiply it by 100 you will arrive at the original 100% amount which is 108000

You then need to adjust your energy up 2.5% so divide 108000 by 100 and multiply it by 102.5 you will arrive at your answer of 110700

There maybe a simpler way to calculate this but the above is the way my brain organises it.