Speedy Oil provides a single-channel automobile oil change and lubrication service. Customers provide an arrival rate of 4 cars per hour. The service rate is 5 cars per hour. Assume that arrivals follow a Poisson probability distribution and that service times follow an exponential probability distribution. a. What is the average number of cars in the system

4 customers

Step-by-step explanation:

Given that:

Mean Arrival rate (λ) = 4 cars per hour

Service rate (u) = 5 cars per hour

Using the queuing formula :

The average number of cars in the system can be obtained using the relation :

Number of customers in the system (L)

Number of customers in queue = (Lq)

L = Lq + (λ/u)

Lq = λ^2 / u(u - λ)

Hence,

Lq = 4^2 / 5(5 - 4)

Lq = 16/ 5(1)

Lq = 16/ 5

Lq = 3.2

L = 3.2 + (4/5)

L = 3.2 + 0.8

L = 4