The supervisor at the Precision Machine Shop wants to determine the staffing policy that minimizes total operating costs. The average arrival rate at the tool? crib, where tools are dispensed to the? workers, is 5 machinists per hour. Each? machinist's pay is ?$15 per hour. The supervisor can staff the crib either with a junior attendant who is paid ?$9 per hour and can process 14 arrivals per hour or with a senior attendant who is paid $18 per hour and can process 20 arrivals per hour.

Which attendant should be? selected?  

The (junior attendant, senior attendant) should be? selected, with a total estimated hourly cost of $.

?(Enter your response rounded to two decimal places?.)