If the average number of customers served per hour is four,then the probability that the service exceeds 15 minutes for any customer is ______.
A)74.1%
B)54.9%
C)36.8%
D)17.4%

Question

Quizplus · Accepted Answer

The average rate is 4 customers per hour, which means the average service time is 15 minutes per customer. The probability that service time exceeds 15 minutes is the probability that an exponential random variable with rate 4 is greater than 1/4, which is e^(-1) ≈ 0.368 or 36.8%.

If the Average Number of Customers Served Per Hour Is