Question

A square piece of cardboard with each side 30 inches long hasa

square cut out at each corner. the sides are then turned up toform
an open box. Find the side of the cut-out square that willproduce a
box of maximum volume.

Answer 1

Answer: 5 inches

Explanation:

V = S * (30-2S)^2

V = S(900-120s+4s^2)

Volume = 4s^3 -120s^2 +900s

Find local maximum from graph at 5 (or take derivative = 0)