Leyland Motors Can Service an Average 5 Cars Per Hour

Multiple Choice

Leyland Motors can service an average 5 cars per hour, and the owner of Leyland Motors wants to know the probability of various customer arrival rates. Given the average arrival rate of 4 customers per hour, the owner uses the Poisson distribution to calculate the probabilities of various customer arrivals per hour.
-What is the probability that, at most, 3 of the customers will arrive within 1 hour?

A) 0.2381
B) 0.4335
C) 0.5665
D) 0.1954
E) 0.7619