Unformatted text preview: ship. Assume that it takes a random time which is exponentially distributed with
mean 10 min.
(a) Consider the service time of a customer to be the total of driving time and
the processing time. What distribution the service time follows? What is the
mean and the coe cient of variation.
(b) What is the fraction of time that the sta↵ is busy (either on his way driving
to a customer or processing a package)?
(c) What is the average waiting of a customer (from making phone call to being
reached by the minivan)?
(d) What is the average number of customers who are waiting for service?
Proof. (a) The service time S ⇠ Erlang (2, 6) with mean E (S ) =
coe cient of variation cs = E (S )...
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