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A cafeteria serving line has a coffee urn from which customers serve themselves Arrivals at the urn follow a Poisson distribution at the rat
Question
A cafeteria serving line has a coffee urn from which customers serve themselves Arrivals at the urn follow a Poisson distribution at the rate of three per minute. Customer service times are exponentially distributed with a mean of 15 seconds.
a) How many customers on average would you expect to see at the coffee station?
b) How long would you expect it to take to get a cup of coffee?
c) What percentage of time is the urn being used?
d) What is the probability that there are three or more people at the coffee station?
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Mathematics
3 years
2021-08-25T09:25:07+00:00
2021-08-25T09:25:07+00:00 1 Answers
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Answers ( )
Answer:
3 ; 1 minute ;75%
Step-by-step explanation:
Given :
Service time = 15 seconds = 15/60 = 0.25 minute per customer
μ = number of customers per minute = 1/0.25 = 4
Arrival rate, λ= 3 persons per minute
L = λ ÷ (μ – λ)
L = 3 ÷ (4 – 3)
L = 3 ÷ 1
L = 3
b) How long would you expect it to take to get a cup of coffee?
L / arrival rate (λ)
3 / 3
= 1 minute
c) What percentage of time is the urn being used?
Utilization rate = λ/ μ
= 3 / 4
= 0.75 = 0.75 * 100% = 75%