A rectangular area of 2,000 square feet is to be fenced on three sides with fence costing $0.30 per foot and on the fourth side with fence costing $0.50 per foot. If x denotes the length of the fourth side and C = f(x) denotes the corresponding cost of the fence in cents.

Express C as a function of x.

0.5x + 1,800/x
0.8x + 1,200/x
0.8x + 1,800/x

Question

A rectangular area of 2,000 square feet is to be fenced on three sides with fence costing $0.30 per foot and on the fourth side with fence costing $0.50 per foot. If x denotes the length of the fourth side and C = f(x) denotes the corresponding cost of the fence in cents.

Express C as a function of x.

0.5x + 1,800/x
0.8x + 1,200/x
0.8x + 1,800/x

anonymous · Answer

OK so you need an expression for the cost. 
What will be the cost of the fourth side? (express it with x)

anonymous · Answer

Now how do i do that?

anonymous · Answer

What is the cost? It is the price*length. Price is given 0.5 dollars. Length is unknown but that is what x represents here.

anonymous · Answer

So that will be 0.5*x or just simply 0.5x

anonymous · Answer

But that is only the price of one side, and we need the full price. What information is given that we havent used yet?

anonymous · Answer

The three equations at the bottom are answer choices

anonymous · Answer

Yes I know that

anonymous · Answer

A rectangular area of 2,000 square feet is to be fenced on three sides with fence costing $0.30 per foot
This part we havent considered yet. 
It has a lot of things that will help you. 
Gives the price of the other 3 sides
Gives the shape 
Gives the area of this shape

anonymous · Answer

i believe its 0.8x + 1,200/x  but im not sure

anonymous · Answer

I havent done any calculation, just trying to help you solve it

anonymous · Answer

Yes you are right, hope you know the calculation for it too :-)