There Is a Tutoring Lab at a University That Holds

Short Answer

There is a tutoring lab at a university that holds 20 students.Due to the popularity of the 3 tutors, the lab is always at capacity.Each student approaches a tutor an average of 2 times per hour, and a tutor spends on average 5 minutes per question from a student.The service time follows an exponential distribution.
(a)What proportion of the time are the tutors busy?
(b)What is the average waiting time for students in queue?