n advising center with a single advisor has space for at most 5 students. Assume that if a student arrives and sees 5 other students waiting, the student leaves without entering the center. Assume that students arrive at a Poisson rate of 3 students per hour, and the successive service times are independent exponential random variables with mean 15 minutes. (a) (5 points) What is the average number of students in the system? Draw the rate diagram, clearly defining the states and label all transition rates