Consider a bank with five tellers and one queue. The bank opens at 9am and closes at 5pm but stays open until all the customers in the bank at 5pm have been served. Customers arrive at rate of 1 per minute, and the inter-arrival times are exponentially distributed. Service times are independent and identically distributed exponential random variables with mean of four minutes. Customers are served in the order in which they arrive. determine the number of replications such that the half-width of the 90% confidence interval is smaller than 0.30. Solve by arena model