A friend of yours wants to teach a dance class after school. She needs to rent a dance studio to teach the class, and the cost of rent is $400 for 12 weeks. The class will meet each week and your friend will charge each student the same fee for the whole course. Your friend's profit depends on how many students enroll in the course and how much she charges each student.
If your friend charges each student D dollars for the course, define a function, p, that relates the number of students who take the dance course, n, to the profit, p(n).