PV Gap

Becky Said:

I don't get this question!!!!Energy and Electricity.?

We Answered:

So it puts out 100 watts on the average and it can do this for 200000 hours at a cost of £ 4000

100 watts x 200000 hours is 20000 kw-hrs
£ 4000 / 20000 kw-hrs = 400p/20 kw-hr = 20 p/kw-hr

it's just dimensional analysis, very simple, plus common sense.