calculus word problem

Question

A train service carries 20,000 people daily between Rationalia and Real City. The rail line could serve up to 31,000 people. The cost to ride the train is $π, but research shows that for each fare increase of $0.02, ridership will go down by 271 people.

1. Create a function to represent the revenue of the train service after xincreases of $0.02. 
2. Given the constraints of the problem, what is the domain of your function? 
3. What fare should be charged to maximize revenue? 
4. If each rider costs the rail service $0.10, what fare should be charged to maximize profit? 

Answer 1

I glossed over a number of details because of time restraints, but this hits the major points.