During manufacturing, the last two things that are done to a dirigible before its manufacture is complete are installing the engine and putting on the landing gear tires (this is one of the single engine dirigibles). An average of 27 dirigibles per hour arrive requiring these two tasks. One worker is available to install the engine and can service an average of 34 dirigibles per hour. After the engine is installed, the dirigible goes to the tire station and waits for its tires to be attached. Three workers serve at the tire station. Each works on one dirigible at a time and can put tires on a dirigible in an average of 7 minutes. Both interarrival times and service times are exponential.

1. Determine the mean queue length at each work station.

2. Determine the total expected time that a dirigible spends waiting for service.

3. We have specified an arrival of 27 dirigibles per hour. What would it mean, that is, what would happen if 37 dirigibles arrived per hour?