$3.$ Benny the Barber $($see the above problem$)$ is considering the addition of a second chair and

another barber. Customers would be selected for a haircut on a first come first served basis from

those waiting. Benny has assumed that both barbers would take an average of $20$ minutes to give

a haircut, and that the business would remain unchanged with customers arriving at a rate of two

per hour. Find the following information to help Benny decide if a second chair should be added:

$(4$ points$)$

$($e$)$ The average number of customers waiting.

$($f$)$ The average time a customer waits.

$($g$)$ The average time a customer is in the shop.

$($h$)$ The average utilization of Benny$$s and second barber$$s time.