The bank manager of a busy downtown location found herself unable to find good teller help so she invested in an ATM to handle the routine withdrawals that tended to occupy an inordinate amount the teller's time. Before she installed the ATM she found that customers were arriving on average every 60 seconds (Poisson distributed) and it took a teller 20 seconds (exponentially distributed) to process their request. The ATM is able to maintain a constant 30 second service time. What is the impact on the waiting time for the customers?