Answer: If the service rate is 6 customers per hour, the mean service time can be calculated as 1/6 = 0.1 hours or 6 minutes. The negative exponential distribution is commonly used to model the service time distribution in queuing theory. The cumulative distribution function (CDF) of the negative exponential distribution is given by:
F(x) = 1 - e^(-λx)
where λ = 1/μ, where μ is the mean service time (in this case, μ = 0.1 hours or 6 minutes).
So, the probability that the service time will be less than or equal to 6 minutes can be calculated as:
F(6) = 1 - e^(-0.1 * 6) = 1 - e^(-0.6) ≈ 0.5488
So, the answer is approximately 0.549, which is closest to option (b).
Explanation: