Eh hmmm

But its incorrect

No it isn't!  EP has correctly answered the question you supplied.  If you think that answer is incorrect you might well have specified the question incorrectly.

I found that the question is same as i am finding it.

https://ask.manytutors.com/questions/114797

Here it is. If you think its correct, what have you done so far?

EP's result is 720 lights.

1/3 of 720 is 240 so each small tree has 240/12 = 20 lights.

The remainder is 720 - 240 = 480 lights.  3/4 of 480 = 360 lights, so each big tree has 360/10 = 36 lights.

Therefore each big tree has 36 - 20 = 16 more lights than each small tree.

Wait nevermind, you're actually correct. Sorry for the inconvenience