Customers arrive at a bank facility at the average rate of 20 per hour, according to a Poisson distribution. There is only one teller window capable of serving 25 customers per hour on the average with exponential service times. Customers form one line, going to the available teller on the bases of FCFS. The bank facility has space sufficient only for a total queue size of 27 clients. If the space yard is full new arriving clients balk to other facilities. The average number of customers waiting in the system is ____________. A) a less than or equal to 4 customers B). Greater than 4 but ≤ 6 customers C) Greater than 6 customers but ≤ 8 customers d. Greater than 8 customers
