A super market has two girls attending to sales al counters. It the service time for each oustomer is exponential wiln mean 4 minutes and if people arrive in Poisson fashion al the rale of 10 per hour, (c) If a customer has to wait in the queve, what is the expected length of his wailing lime? ( $3 \times 20=60$ Marks)

Explanation

The expected waiting time for a customer is given by Lq = ρ^2 / (1 - ρ) * 1/μ. In this case, Lq = 16/63 minutes.