Let each side perpendicular to the river be "x".Then the side parallel to the river is "400-2x".
The formula for Area = width*length
A(x) = x(400-2x)
A(x) = 400x - 2x^2
You have a quadratic with a = -2 and b = 400
Maximum Area occurs where x = -b/2a = -400/(2*-2) = 100 ft. (width)
length = 400-2x = 400-2*100 = 200 ft (length)
I believe the answer is D. $34.43
[15 + 1/2 ] - [ 2 + 3/4 ] - [6 + 2/3 ]......convertng these to improper fractions, we have
[31 /2 ] - [11 / 4 ] - [ 20 / 3 ] getting a common denominator (12), we have
[186 / 12] - [33 / 12 ] - [ 80 / 12 ] = 73 / 12 inches = about 6.0833 inches left
X=1 so you need to add and it will be c=9
