2. The average number of airplanes that can land at an airport is 12 planes per hour and the average arrival rate is 9 planes per hour. The cost of operating a plane (i.e., the cost of it circling the airport, waiting to land) is $5400 per plane per hour. The cost of landing a plane is $1200 per plane a. What is the mean number of planes in the system? b. What is the average time a plane spends circling the airport? c. Find the total hourly cost of operation at current conditions d. Find the optimal service rate2. The average number of airplanes that can land at an airport is 12 planes per hour and the average arrival rate is 9 planes per hour. The cost of operating a plane (i.e., the cost of it circling the airport, waiting to land) is $5400 per plane per hour. The cost of landing a plane is $1200 per plane a. What is the mean number of planes in the system? b. What is the average time a plane spends circling the airport? c. Find the total hourly cost of operation at current conditions d. Find the optimal service rate