7. A call center with infinite capacity and only one operator can be modeled as an M/M/1 queueing system. Assumed that the number of customers calling the call center follows a Poisson process with mean rate of 5 per hour. The time each customer spends with the operator is highly variable and is approximated by an exponential distribution with mean time of 10 minutes a. Find the traffic intensity p of the system. b. What is the probability that the system contains 3 customers in the long run? Find the expected number of customers in the system. d. Find expected time spend by each customer in the system. C