The point is that LawnmowerMan got several perfectly good answers starting with the formula posted by Sid (who is mine btw, so fuck off Michael) in the beginning and later by Kartoffel and then even an explanation by Michael and all they got for it was more flaming because LawnmowerMan didn´t even try to understand those answers. Probably because its math...
I could try to explain why Sids formula was already a perfect solution, but I guess I would still only be the asshole that decided to side with the ones having the wrong opinion. As a result I don´t even try to explain.

Seriously guys, Sid is right and didn´t even start all the flaming. If you don´t understand something just ask follow up questions, but at least show everyone that you tried.