4. WAITING LINE MODELS The airport security check has multiple screening stations available, and the security manager must decide how many to have open at any particular time. The service rate for processing passengers at each screening station is 2 passengers per minute. The arrival rate is 5.4 passengers per minute. Assume that processing times at each screening station follow an exponential distribution and that arrivals follow a Poisson distribution. a) The facility manager's goal is to limit the average number of passengers waiting in line to 10 or fewer. How many screening stations must be open in order to satisfy the manager's goal, assuming a probability that no units are in the system is Po= 0.02525? (3 marks) b) What is the average time required for a passenger to pass through security screening