All airplane passengers at the Lake City Regional airport must pass through security screening before proceeding to the boarding area. The airport has 8 screening stations available, and the facility manager must decide how many to have open at any particular time. The average service time for processing passengers at a screening station is 50 seconds per passenger. On Monday morning, the inter-arrival time is one-third of a minute per passenger. Assume exponential service times and Poisson arrival rates. The airport policy is to open the minimum number of screening stations that will ensure a 99% probability that the maximum line length is 5 passengers or fewer. How many screening stations should be opened