Algebra
posted by Carson .
Biologists want to set up a station to test alligators in the lake for west nile virus. Suppose that the cast for such a station are $2,500 for set up costs and $3.00 to administer test.
a. Write an expression that gives the total cost to test x animals.
b. You can find the cost per animal by dividing total costs by number of animals. Write the expression that gives the average cost per animal.
c. Find the average cost per animal for 10 animals, 100 animals, and 1,000 animals.
d. As the number of tested animals increases, what happens to the average cost to test? Would the average cost ever fall below #3.00? If so, identify that value. If not explain.
e. How many animals should be tested for the average cost to be $5.00 per animal?
I have a good start, but want to make sure I am using the correct formulas, can you help?

c = 2500 + 3 x
av cost = (2500+3x)/x
note for part d that can be written:
av cost = 2500/x + 3