Janson's Department Store in​ Stark, Ohio, maintains a successful catalog sales department in which a clerk takes orders

[answerhappygod]

Janson's Department Store in​ Stark, Ohio, maintains a
successful catalog sales department in which a clerk takes orders
by telephone. If the clerk is occupied on one​ line, incoming
phone calls to the catalog department are answered automatically by
a recording machine and asked to wait. As soon as the clerk
is​free, the party who has waited the longest is transferred and
serviced first. Calls come in at a rate of about 10 per hour. The
clerk can take an order in an average of 3.0 minutes. Calls tend to
follow a Poisson​distribution, and service times tend to be
negative exponential.
The cost of the clerk is ​$8 per​ hour, but because of lost
goodwill and​ sales, Janson's loses about ​$30 per hour
of customer time spent waiting for the clerk to take an order.
a) The average time that catalog customers must wait before
their calls are transferred to the order clerk​ =?
minutes ​(round your response to two decimal​ places).
​b) The average number of callers waiting to place an
order​ =? callers ​(round your response to two
decimal​ places).
The present total cost per hour​ (service cost+waiting
​cost) =? per hour ​(round your response to two
decimal​ places).
​c) Janson's is considering adding a second clerk to take calls.
The ​store's cost would be the same ​$8 per hour. The total
cost​ (service cost+waiting ​cost) =? per hour
​(round your response to two decimal​places).
By hiring the second​ clerk, the total cost savings per
hour for​ Janson's = ? per hour ​(round your response to
two decimal​ places).