Question

Combined area of 1680ft^2 for 4 identical rectangular corrals.

Corrals are joined together and no fencing at the back wall of the barn.

200=5d+4w
1680=4dw

What length will produce the maximum area?
d=12
The dimensions of each corral (lxw) is 12'x35'
What will be the resulting maximum combined area of 4 corrals? The combined area would also mean maximum area, correct?

A=dw
A=(4)(12)(35)=1680ft^2

Answer 1

for maximum area, consider

a = 4dw = 4w(200-4w)/5
maximum a at w = 25 (midway between the roots of 0,50)

4dw = 75*25 = 1875 is the maximum area