Customers arrive at Paul Harold's Styling Shop at a rate of 3 per hour, distributed in a Poisson fashion. Paul can perform haircuts at a rate of 5 per hour, distributed exponentially.
a) Find the average number of customers waiting for haircuts
b) Find the average number of customers in the shop
c) Find the average time a customer waits until it is his or her turn
d) Find the average time a customer spends in the shop
e) Find the percentage of time that Paul is busy