(Bank Branch) One teller has been serving all customers at a local bank branch in a small town of Boston. Customers arrive in a mean of 1/15 hours (or 4 minutes) with a standard deviation of 1/15 hours. The teller spends a mean of 1/20 hours (or 3 minutes) with a standard deviation of 1/20 hours. Customers visit the branch for different tasks, which creates the variability of service times. Some of their requests, such as money withdrawals, take a short time whereas others such as foreign money deposits take long. (Bank Branch) --- Use the posted queueing template to find average flow time (W). --- Use the Little's law to find average customers in the entire system (L). (Hint: L includes customers in the waiting line and those in service.)