A Street Noodle Vendor (One Server) in Singapore Can Service

Multiple Choice

A street noodle vendor (one server) in Singapore can service an average of 20 customers per hour. Given an average arrival rate of 12 customers per hour, use the Poisson distribution to calculate the probability that the vendor can handle the demand.
-Calculate the mean number of customers in the system (being served and in the queue) .

A) none
B) 2.6
C) 1.5
D) 3.4
E) 4.2