Question:

(a) Distinguish between
(i) a single-channel and a multiple-channel waiting line;
(ii) a birth and a death process with regard to queueing theory.

(b) Explain briefly three common types of customer's behaviour.

(c) A tax consulting firm has three service stations in its office to receive customers who have complaints about their income, wealth and sales taxes. The average rate of arrivals is 7 customers per hour. Each tax adviser spends an irregular amount of time servicing arrivals which have been found to follow an exponential distribution.

The average service time is 15 minutes per customer. Find the

(i) traffic intensity.
(ii) average number of customers in the system.
(iii) average time a customer has to wait before he gets service.