When put in a calculator, the answer is 12.22 (recurring)
About 204 students would choose summer , I found this because 25% is one quarter of a whole and to get the whole you multiply by four so take 51 and multiply by four to get 204
That’s not enough information to say how long he could do it. He could go slower or faster than her but by how much if so. So it’s not enough info.
Check the picture below. Recall, is an open-top box, so, the top is not part of the surface area, of the 300 cm². Also, recall, the base is a square, thus, length = width = x.

so.. that'd be the V(x) for such box, now, where is the maximum point at?

now, let's check if it's a maximum point at 10, by doing a first-derivative test on it. Check the second picture below.
so, the volume will then be at