Customers Arrive at a Common Queue at the Coffee Station

Multiple Choice

Customers arrive at a common queue at the coffee station with two identical coffee machines in a busy mall at the rate of 48 per hour, following Poisson distribution. Each customer mixes his or her specialty coffee taking 2 minutes on an average following an exponential process. What is the expected number of customers in the system at this coffee station?

A) infinity
B) 2.844
C) 2.444
D) 4.444
E) 3