A bank has two teller counters to serve customers. The average number of customers who come to the bank is 30 customers per hour, with the distribution of arrivals following the Poisson distribution. Each teller has an average service time of 2 minutes per customer, with the service time distribution following an exponential distribution. Answer the following questions!
a) Average number of customers in the queue.
b) Average customer waiting time in queue before being served.
c) The probability that there are no customers in the queue.
d) The probability that all tellers are serving customers when two new customers arrive at the same time.
e) If the bank decides to add one additional teller counter, what is the average time
customers wait in line before being served? Explain your decision!