The National Bank of Union City currently has one outside drive-up teller. It takes the teller an average of three minutes (exponentially distributed) to serve a bank customer. Customers arrive at the drive-up window at the rate of 12 per hour (Poisson distributed). The bank operations officer is currently analyzing the possibility of adding a second drive-up window at an annual cost of $20,000. It is assumed that arriving cars would be equally divided between both windows. The operations officer estimates that each minute’s reduction in customer waiting time would increase the bank’s revenue by $2000 annually. Should the second drive-up window be installed? What other factors should be considered in the decision besides cost?