Multiply 120 times .7 because you just Turn the percent into a decimal
Aas is not d triangle buddy
(0.65+0.4+0.35)-0.10 is equal to 1.3
combining like terms is how you solve this problem
So hmm notice the picture below
thus, the perimeter of the gutter is just w + w + l, or 2w +l
thus

take the derivative of A(w), zero it out, check any critical points in the interval of (0, 22), for a maxima
recall, the aluminum sheet is just 22inches long, thus, whatever the "depth" or "w" is, has to be more than 0, and less than 22