Barber College is the best deal in town! For only $5,you can get a shampoo and cut by any one of four untrained stylists completed in 7.5 minutes on average.Perhaps this is why customers show up on average two minutes apart (both interarrival times and service times are exponentially distributed).
-What percentage of the time are the four stylists working with customers?
A)94%
B)90%
C)84%
D)80%

Question

Quizplus · Accepted Answer

The arrival rate is 1 customer every 2 minutes (0.5 customers per minute), and the service rate is 1 customer every 7.5 minutes (0.1333 customers per minute per stylist). With 4 stylists, the total service rate is 4 * 0.1333 = 0.5333 customers per minute. The utilization rate is the arrival rate divided by the total service rate: 0.5 / 0.5333 = 0.9375 or 94%.

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