a bank is opening a new location in a business district. they have to determine how many teller windows to have open during the busy lunchtime hour. the demand during this hour is forecasted to be normally distributed with a mean of 23 customers and a standard deviation of 10 customers. the average business revenue generated from each customer is $25 and each customer takes an average of five minutes to be served. tellers are paid an hourly wage of $20. how many teller windows should the bank have open? 1? 2? 4