In: Operations Management
The Robotics Manufacturing Company operates an equipment repair business where emergency jobs arrive randomly at the rate of three jobs per 8-hour day. The company's repair facility is a single-server system operated by a repair technician. The service time varies, with a mean repair time of 2 hours and a standard deviation of 1.5 hours. The company's cost of the repair operation is $28 per hour. In the economic analysis of the waiting line system, Robotics uses a $35 per hour cost for customers waiting during the repair process.
Current System (σ = 1.5) | New System (σ = 0) | |
---|---|---|
Lq | ||
L | ||
Wq | ||
W | ||
TC | $ | $ |
a) What are the arrival rate and service rate
in jobs per hour?
Round your answers to three decimal places.
Arrival rate = jobs per hour
=8hours/3 jobs= 2.666 hours per job
Jobs per hour=1/2.666
Ans= λ =.375 jobs per hour
Service rate = jobs per hour
= 1 repair job /2 hours
μ =.5 jobs per hour
b.
Show the operating characteristics, including the total cost per
hour.
Round your answers to four decimal places.
Lq = λ 2 62 + (λ / μ)2 / (2(1- λ / μ)
=(.375x.375)(1.5x1.5)+(.375/.5)2/(2(1-.375/.5)=.1406x2.25+.5625/ .5
=.8789/.5=1.7578/hour
L = Lq + λ /
μ=1.7578+.375/.5= 2.5078/ hour
Wq=Lq/ λ =4.688 hour or 281.28 minutes
W=L/ λ = 6.688 hour or 401.28 minutes
Pw= λ /μ=.75
Round your answer to the nearest cent.
TC=CwL+Csk=35x2.508+28x1=$ 115.78
TC = $ 115.78
C.
d. Yes; Savings = 40 ($115.77 - $97.63) = $725.60
Note: Even with the advantages of the new system, W q= 3 shows an average waiting time of 3hours. The company should consider a second channel or other ways of improving the emergencyrepair service