Cars arrive at fast food drive through window according to a
Poisson process with the average rate of 1 car every 10 minutes.
The time each customer spends ordering and getting food is
Exponential with the average time of 3 minutes. When a customer is
served, the other arrived customers stay in a line waiting for
their turn.
How many of the following statements are correct?
a) the expected number of cars in the line at any time is
9/70.
b) the proportion of time when nobody is served at the drive
through window is 0.7.
c) the expected time it takes to follow the drive through lane,
from arrival till departure, is 30/7 min.