Create a diagram of the adjacent rectangular pens with width, W, and length, L.
The perimeter of these enclosures requires 2 sections of width and 3 sections of length.
Thus p = 2W + 3L = 480 and isolating w gives W = (- 3/2L + 240)
A = LW = -3/2L2 +240L
A' = -3L + 240 = 0 ; L = 80 , W = 120 and the maximum area enclosed = 9,600 ft2. Each adjacent corral is 60' x 80'.