Question

A farmer wants to fence in a rectangular plot of land adjacent to the north wall of his barn. no fencing is needed along the barn, and the fencing along the west side of the plot is shared with a neighbor who will split the cost of that portion of the fence. if the fencing costs $12 per linear foot to install and the farmer is not willing to spend more than $3000, find the dimensions for the plot that would enclose the most area. (width, length) =

Answer 1

Hi,

Let assume a the west side,

b the length of the north wall (i suppose the answer is smaller then the barn.

Cost of the fence= a*6+a*12+b*12=3000 $.

So 3a+2b=500==>b=(500-3a)/2

Area =a*b=a(500-3a)/2= 250a-3/2a²

Derivate the area ==> 250-3a=0

==> a=250/3 and b=(500-3*250/3)/2=125

Width=125 (feet)

Length=250/3=83.333 (feet)