Question

A box with an open top is to be constructed from a rectangular piece of cardboard with dimensions W inches by L inches by cutting out equal squares of side x at each corner and then folding up the sides. (W = 12 in. and L = 20 in). Find the values of x for which the volume is greater than 200 in3. (Give each answer correct to three decimal places

Answer 1

v = x(W-2x)(L-2x)
so,

x(12-2x)(30-2x) > 200
8-3√6 < x < 5