The box office at the minor league baseball stadium uses a multiple channel queuing system, all customers that arrive wait in a single line for the first available ticket clerk. If the average service time to purchase a ticket is 1.5 minutes and the average arrival rate is 7 customers every five minutes, find the following:

a.	The minimum number of windows to be open to allow for a feasible system.
b.	When three service windows are open, what is the probability both windows are idle.
c.	When four service windows are utilized, what is the average number of customers waiting in line.
d.	When fourservice windows are utilized, what is the average time a customer waits in line.
e.	When fiveservice windows are utilized, what is the the average time a customer is in the bank?