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Question 5 A post office has a counter for customers drive-through to get the services. The design of the drive-through lane allows for unlimited queue length. The arrival and service rate are Poisson distributed with A= 20 customers per hour arriving on average and y =25 customers per hour can be served on average. a) Compute the average number of arrivals. (2 Marks) b) Compute the average time a customer waits. (2 Marks) c) Compute the average number of arrivals in the system. (2 Marks) d) Compute the average time a customer is in the system. (2 Marks) e) Compute the probability that less than or equal to 3 customers are in the system. (3 Marks) 1) If the single counter for the customer drive-through has been replaced with the automatic operation, service rates are constant with A=20 and u =25. Compute (a), (b), (c) and (d). (4 Marks) (Total :15 Marks)