A Crew of Mechanics at the Department of Transportation Garage

Multiple Choice

A crew of mechanics at the Department of Transportation garage make minor repairs to snowplows during the winter. The snowplows break down at an average rate of 4 vehicles per day and breakdowns are distributed according to the Poisson distribution. The mechanic can service an average of 7 vehicles per day with a repair time distribution that approximates a negative exponential distribution. Assume an 8 hour day.
-What is the expected average number of snowplows in the garage (waiting for repair and being repaired) ?

A) 1
B) 1.33
C) 2
D) 2.52