Question

The First American Bank of Rapid City has one outside drive-up teller. It takes the teller an average of 4 minutes to serve a bank customer. Customers arrive at the drive-up window at a rate of 12 per hour. 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 $2,000 annually. Should the second drive-up window be installed.

Please put in excel format.

ONE TELLER
Wq =
TWO TELLERS
Wq =
REDUCTION IN WAITING TIME =
ANNUAL INCREASE IN BANK REVENUES =
ANNUAL COST OF ADDITIONAL WINDOW =
BENEFIT FROM ADDING A SECOND WINDOW =

Answer 1