$($PLEASE SOLVE IN EXCEL! SHOW STEPS PLZ$!)$

Calls to the service center at AutoMax occur at a rate of $27$ per hour and follow a Poisson distribution. A single operator answers the calls and can handle an average $25$ calls per hour with service times following an exponential distribution. If a call arrives while the operator of AutoMax$$s phone system is busy with another customer, up to $2$ callers may be placed in a queue to await service. If a call arrives when the queue is full the caller receives a busy signal.

A$.$ What is the probability that a caller waits in the queue?

B$.$ How many minutes can customers expect to wait in the queue?

C$.$ What is the probability that a caller receives a busy signal?

D$.$ What should be the maximum queue length if AutoMax wants there to be no more than approximately a $0\mathrm{.}2$ probability that calling customers receive a busy signal?