Question

Speedy Oil provides a single-server automobile oil change and lubrication service. Customers provide an arrival rate of 2.5 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. What is the average number of cars in the system

Answer 1

the average number of car(s) in the system is 1

Explanation:

Given the data in the question;

Arrival rate; λ = 2.5 cars per hour

Service time; μ = 5 cars per hour

Since Arrivals follows Poisson probability distribution and service times follows exponential probability distribution.

Lq = λ² / [ μ( μ - λ ) ]

we substitute

Lq = (2.5)² / [ 5( 5 - 2.5 ) ]

Lq = 6.25 / [ 5 × 2.5 ]

Lq = 6.25 / 12.5

Lq = 0.5

Now, to get the average number of cars in the system, we say;

L = Lq + ( λ / μ )

we substitute

L = 0.5 + ( 2.5 / 5 )

L = 0.5 + 0.5

L = 1

Therefore, the average number of car(s) in the system is 1