What are the dimensions of the piece of metal?

Question

A rectangular piece of metal is 25 in longer than it is wide. Squares with sides 5 in long are cut from the four corners and the flaps are folded upward to form an open box. If the volume of the box is 750in^3, what were the original dimensions of the piece of metal?

Answer 1

L=25+W

(L-10)(W-10)5 = 750

(25+W-10)(W-10) = 150

(W+15)(W-10)= 150

W^2+5W -150 = 150

W^2 +5W -300 = 0

W=-5/2 + o r -(1/2) sqr(25+1200)

= -5/2 + (1/2)sqr(1225) = -5/2 +35/2 = 15 inches

L=25+15 = 40 inches

Volume = (40-10)(15-10)5 =30x5x5=750 in^3