At time ? = 0, when the border inspection station was scheduled to open, eight vehicles were already waiting in a queue in front of an inspection booth. Vehicles continued to arrive at a rate of 4 veh/minute. The officer did not start the inspection until ? = 4 minutes. When ?≥4 minutes, the barrier was lifted and vehicles left at a rate of 7.5 veh/minute. Draw the vehicle arrival and departure curves in the following graph. From the graph, determine the maximum queue length and the time the queue disappears. Assume D/D/1 queuing.

At time ? = 0, when the border inspection station was scheduled to open, eight vehicles were already waiting in a queue in front of an inspection booth. Vehicles continued to arrive at a rate of 4 veh/minute. The officer did not start the inspection until ? = 4 minutes. When ?≥4 minutes, the barrier was lifted and vehicles left at a rate of 7.5 veh/minute. Draw the vehicle arrival and departure curves in the following graph. From the graph, determine the maximum queue length and the time the queue disappears. Assume D/D/1 queuing.