Need help with this problem.

A rectangular area adjacent to a river is to be fenced in, but no fencing is required on the side by the river. The total area to be enclosed is 1000 square feet. Fencing for the side parallel to the river is $5 per linear foot, and fencing for the other two sides is $8 per linear foot. The four corner posts cost are $25 apiece. Let x be the length of one of the sides perpendicular to the river.

a) Write a function C(x) that describes the cost of the project.
b) What is the domain of C?

Question

Need help with this problem.

A rectangular area adjacent to a river is to be fenced in, but no fencing is required on the side by the river. The total area to be enclosed is 1000 square feet. Fencing for the side parallel to the river is $5 per linear foot, and fencing for the other two sides is $8 per linear foot. The four corner posts cost are $25 apiece. Let x be the length of one of the sides perpendicular to the river.

a) Write a function C(x) that describes the cost of the project.
b) What is the domain of C?

ranga · Answer

A picture would help:

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ranga · Answer

Length of side perpendicular to the river = x
Length of side parallel to the river = L

Area = Lx = 1000.  Therefore, L = 1000 / x

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