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$)$

The average number of customers waiting:

$2^2/6*(6-2)$

The average time a customer waits.

The average time a customer is in the shop.

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