Question

A private shipping company will accept a box for domestic shipment only if the sum of its length and girth​ (distance around) does not exceed 108 inches. Suppose you want to mail a box with square sides so that its dimensions are h by h by w and its girth is 2 h plus 2 w. What dimensions will give the box its largest​ volume?

Answer 1

18×18×36

Explanation:

According to the Question

108≥ 4h + w

Volume V is given by

V = wh^2

⇒V= (108-4h)h^2

⇒V= 108h^2 - 4h^3

Now differentiating and keeping = 0 we get

V' = 216h - 12h^2 = 0

h = 216/12 = 18

w = 108 - 4×18 = 36

V = 36×18^2 = 11664 from a box of 18×18×36.