average, 100 customers arrive per hour at Gotham City Bank. It takes a
teller an average of 2 minutes to serve a customer. Interarrival and
service times are exponentially distributed. The bank currently has 4
tellers working. The bank manager wants to compare the following two
systems with regard to the average number of customers present in the
bank and the probability that a customer will spend more than 8 minutes
System 1: Each teller has his or her own line (and no moving between
lines is permitted). Arriving customers are equally likely to choose any
• System 2: All customers wait in a single line for the first available teller.
If you were the bank manager, which system would you prefer?
the attached Excel templates that are appropriate for this problem
showing the formation of the model and solution to the problem.