2. Silverman Sachs is a popular bank which has on average 20 clients arriving every hour, with a standard deviation of interarrival times of 2 minutes. There is one line for service, and it is currently operated by two bank tellers. Each teller spends on average 4.5 minutes to assist a client. The service times follow an exponential distribution. a. (6 points) Assume that every client coming to the bank needs assistance, and each must go through the service line. What is the average wait time that a client has to wait in line before getting serviced by the teller? 4.28min b. (4 points) What is the average number of customers who are at the counter, either waiting or currently being served? 2.93 clients c. (4 points) If there are no clients requiring service, the tellers are bundling bills into straps, which there are always plenty of. Suppose that on average it takes 5 mins to bundle a strap (record that it has been strapped and stored in the vault). How many bundles can the two employees strap over a 12-hour shift? 72 bundles d. (3 points) As a special service, the bank offers free snacks for customers waiting in the service line (the customers who are currently served by the checkout employees are already busy with payment, so they do not get free snacks.) The branch manager estimates that every minute of client waiting time costs the bank 75 cents because of the free snack service. What is the hourly cost for the store due to this service? $64.20