For the post office in the previous problem, a second drive-through window is being considered.

For the post office in the previous problem, a second drive-through window is being considered. A single line would be formed and as a car reached the front of the line it would go to the next available clerk. The clerk at the new window works at the same rate as the current one.

• What is the average time a car is in the system?
• What is the average number of cars in the system?
• What is the average time cars spend waiting to receive service?
• What is the average number of cars in line behind the customer receiving service?
• What is the probability that there are no cars in the system?
• What percentage of the time are the clerks busy?
• What is the probability that there are exactly two cars in the system? 

Show work