Trucks arrive at a warehouse at a rate of 27.0 per hour during business hours.

Each crew-and-dock can unload the trucks at a rate of 10 trucks per hour.

Each crew-and-dock is assumed as a server, crew-and-dock are NOT separate units.

The waiting line of trucks have caused the warehouse manager to have 3 crew-and-docks.

Each crew-and-dock can unload one and only one truck at a time.

The cost rates are as follow:
Each crew-and-dock costs $90 per hour; truck & driver waiting cost is $100 per hour.

Assume Poisson arrival and Exponential processing time.

1. Compute the total hourly crew-and-dock costs.

2. Compute the utilization of the crew-and-docks.
3. What percentage of time the crew-and-docks are idle?
4. Compute the total hourly truck-and-drivers cost during the time that the trucks are unloading.
5. Compute the total hourly truck-and-drivers cost when trucks are in the waiting line.
6. Compute the maximum amount you are willing to pay to have one additional crew-and-dock.
7. After adding one crew-and-dock, what is the maximum you can save by adding more and more crew-and-docks?