The federal government is undertaking a massive process analysis of the notoriously chaotic border San Diego and Tijuana. They have selected the San Ysidro station as a sample case and would like your input in doing the following analysis. Automobiles arrive from Mexico at the rate of 20 per hour according to a Poisson distribution. The station has 3 inspection lanes for cars and 1 inspection lane for trucks. All cars join a common queue and go to the first available car inspection lane. About 30% of the incoming vehicles are trucks and the remaining are cars. Average inspection time for a truck is 5 min and average inspection time for a car is 6 min. Also, authorities have noticed that about 50% of the trucks and 25% of the incoming cars need further scrutiny of contents and documents. For this, they are diverted to a separate lane in the San Diego side of the border, where it takes about 8 min per vehicle to get checked thoroughly. This single "close scrutiny" lane is designed to handle both cars and trucks. For your convenience, a simple representation of the system is shown below.