Neve Commercial Bank is the only bank in the town of York, Pennsylvania. On a typical

Friday, an average of $10$ customers per hour arrive at the bank to transact business. There is

currently one teller at the bank, and the average time required to transact business is $4$

minutes. Assuming Poisson arrivals and exponential service times, find the:

$($a$)$ average time in the line.

$($b$)$ average number in the line.

$($c$)$ average time in the system.

$($d$)$ average number in the system.

$($e$)$ probability that the bank is empty.