The United Airlines security station for Terminal C in Indianapolis has 3 X-ray machines. During the busy early morning hours, an average of 400 passengers per hour arrive at Terminal C (with...

The United Airlines security station for Terminal C in Indianapolis has 3 X-ray machines. During the busy early morning hours, an average of 400 passengers per hour arrive at Terminal C (with exponential interarrival times). Each X-ray machine can handle an average of 150 passengers per hour (with exponential service times for X-ray machines). After going through security, 90% of the customers are free to go to their flight, but 10% must be “wanded.” Three people are available to do the wanding. Wanding requires a mean of 4 minutes, with a standard deviation of 2 minutes.

a How long does it take the average passenger to pass through security?

b If there were no wanding, how long would it take the average passenger to pass through security?

c Which would improve the situation more: adding an X-ray machine or adding an additional person to perform wanding?