A Small Popular Restaurant at an Interstate Truck Stop Provides

Multiple Choice

A small popular restaurant at an interstate truck stop provides priority service to truckers. The restaurant has ten tables where customers may be seated. The service time averages 40 minutes once a party is seated. The customer arrival rate is 12 parties per hour, with the parties being equally divided between truckers and non-truckers.
On average, how many parties of truckers are waiting to be seated?

A) 0.27.
B) 0.52.
C) 0.88.
D) 1.36.
E) 1.75.