Suppose the marginal cost of writing a contract of length Suppose the marginal cost of writing a…

Suppose the marginal cost of writing a contract of length
Suppose the marginal cost of writing a contract of length L is MC (L) = 20 + 5L. Find the optimal contract length when the marginal benefit of writing a contract is:
a. MB (L) = 120.
b. MB (L) = 180.
c. What happens to the optimal contract length when the marginal benefit of writing a contract increases?

Suppose the marginal cost of writing a contract of length