11. FISHING A county park sells annual permits to its fishing lake. Last year, the
county sold 480 fishing permits for $80 each. This year, the park is considering
a price increase. They estimate that for each $4 increase, they will sell 16 fewer
annual fishing permits.
a. Define variables and write a function to represent the situation.
b. How much would the park have to charge for each permit in order to maximize
its revenue from fishing permits?
c. Find the domain and range in the context of this situation.