Customers enter the waiting line at a cafeteria on a first-come, first-served basis. the arrival rate follows a poisson distribution, while service times follow an exponential distribution. if the average number of arrivals is four per minute and the average service rate of a single server is seven per minute, what is the average number of customers in the system?

a.0.43
b. 1.67
c. 0.57
d. 1.33
e. none of the above

The average number of customers in the system is 1.33 customers (option D).

Step-by-step explanation:

This is a problem of queing theory (single-server waiting line).

We have that the arrival rate is and the service rate is .

The formula for the average number of customers in the system is:

answer: $201

step-by-step explanation: to get the answer, you first get 3 nieces that he sold and multiply it by 67 and get $201, so he earned $201 selling his nieces.