Flying Lukas needs to check in at Philadelphia Airport to take his US Airway flight to Boston. He can choose either to check in with a self-service counter or with an agent. During busy periods, a new passenger walks to a self-service counter every minute (with a standard deviation of 1 minute). The passengers who want to check in with an agent walk in every 5 minutes (with a standard deviation of 5 minutes). There are 5 self- service counters installed, while there are two agents. A typical check-in process takes 4 minutes (with a standard deviation of 4 minutes), regardless of whether an agent or a self- service counter. 3.1. If Flying Lukas walks to a self-service counter to check in during a busy period, how long must he wait (on average) in line before he can use the machine?