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.
-Change the number of customers the street vendor can serve per hour from 20 to 15. What is the probability that there is more than 1 customer in the system at any given time?

A) 50%
B) 36%
C) 64%
D) 20%
E) 16%