Math algebra help please

Question

suppose that you wish to build a rectangular cement patio that is to have a perimeter of 80 feet the length is to be 5 feet more than the width. A. Find the dimensions of the patio. B. If the building code requires that the cement be 4 inches deep how much cement do you have to purchase??

Answer 1

P=80 = 2(L+W) = 2(W+5 + W) = 2(2W+5) = 4W + 10

4W + 10 = 80

4W = 70

W = 17 1/2 feet

L = 22 1/2 feet

80 = 2(17 1/2 + 22 1/2) =2(40)