Problem: A multiple channel queuing system with a Poisson arrival rate, and an exponential service time distribution has an average arrival rate of 2.5 customers per hour and an average service time of eighty minutes per customer. A queuing system is described as unstable or overloaded if its utilization rate is greater than, or equal to one. For the system just described, what is the minimum number of servers required to retain stability i.e., to avoid overloading?