At a currency exchange bureau, on average a customer arrives every 5 minutes and takes 4 minutes to be served. Considering the assumptions of a single channel queuing model, determine the following: i) The traffic intensity. ii) The probability the cashier is idle. iii) Expected no. of customers in the system. iv) The average length of the queue. v) The mean time a customer spends in the system. vi) The mean time a customer spends in the queue.