A bank has an inside teller operation with two windows and a drive-through. Teller 2 works both inside and is responsible for the drive-through, while Teller 1 works only inside. Cars arrive to the drive-through uniformly every 5 to 15 minutes. Inside customers arrive uniformly every 10 to 20 minutes. Transaction times at the drive through are exponential with a mean of three minutes. Times for inside transactions are exponential with a mean of four minutes. The drive-through has a capacity for only four cars. Develop a SimQuick model, and run it for 600 minutes. Explain the results.