# Math Help - Word Prob Help?

1. ## Word Prob Help?

A drain is to be made up of rectangular aluminum sheets 12 inches wide by turning up the side edges 90 degrees. What depth (of the edges) will provide a maximum cross sectional area and thereby provide for the greatest flow of water

2. Let the length of the fold be x inches. Then the base will have length 12-2x inches. By using $x=\frac{-b}{2a}$ we can find the length of the folded side to maximize area.

Area = $x(12-2x)=-2x^{2}+12x$

a=-2 and b=12

$x=-\frac{12}{2(-2)}=3$

Turn the edges up 3 inches.