Consider an elevator in a building. Suppose that there are N floors above the ground floor, and that each person entering on the ground floor is equally likely to get off at one of these N floors. Suppose also that that no people enter the elevator except on the ground floor and that the elevator will only stop at a floor (above the ground floor) if someone in the elevator wants to get off at that floor. (a) Suppose that k people entered the elevator on the ground floor, find the expected number of stops the elevator will make to discharge all its passengers. (b) Suppose that the number of people entering the elevator on the ground floor is a Poisson random variable with parameter = 10, find the expected number of stops the elevator will make to discharge all its passengers.