Zimmerman’s bank is the only bank in the small town of st. thomas. on a typical friday, an average of 10 customers per hour arrive at the bank to transact business. there are two tellers at the bank (both work at the same rate), and the average time required to transact business is 4 minutes. it is assumed that service times and the inter-arrival times may be described by the exponential distribution. a single line would be used, and the customer at the front of the line would go to the first available bank teller. find: a) the average time a customer spends in the line. b) the average number of customers in the line. c) the average time a customer spends in the system. d) the average number of customers in the system.