American Bank has a single automated teller machine (ATM) located in a shopping center. Data were collected during a period of peak usage on Saturday aftemoon and it was found that the average time between customer arrivals is 2.1 minutes with a standard deviation of .8 minute. It also was found it takes an average of 1.9 minutes for a customer to complete a transaction with a standard deviation of 2 minutes. Approximately how long will customers need to wait in line during the peak usage period?