To support National Heart Week, the Heart Association plans to install a free blood pressure testing booth in EI Con Mall for the week Previous experience indicates that, on average, 20 persons per hour request a test. Assume arrivals are Poisson distributed from an infinite population. Blood pressure measurements can be made at a constant time of two minutes each. Assume the queue length can be infinite with FCFS discipline. a. What average number in line can be expected? (Round your answer to 3 decimal places.)