A one-man barber shop has a total of 10 seats. Interarrival times are exponentially distributed, and an average of 20 prospective customers arrive each hour at the shop. Those customers who find the shop full do not enter. The barber takes an average of 12 minutes to cut each customer’s hair. Haircut times are exponentially distributed.

1 On the average, how many haircuts per hour will the barber complete?

2 On the average, how much time will be spent in the shop by a customer who enters?