For each situation given below show, give the Kendall notation, arrival rate, service rate, number of servers, maximum number in the system, and maximum number in the queue.

a. A professor supervises four Ph.D. students who all need quite a bit of advice. The students are quite similar regarding their habits. When a student visits a professor, the time to the next visit has an exponential distribution with a mean of 4 hours. The time for the professor to advise a student has a mean value of 1/2 hour. This time has an exponential distribution.

b. Calls arrive to a telephone switchboard at a rate of 40 per hour. There are two telephone operators who answer the calls and one holding line. A caller receives a busy signal when both operators are busy and a customer is waiting on the holding line. We assume that such a customer will balk. The time required for the operator to answer a caller has an exponential distribution with a mean of 2 minutes.