A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of 3 vehicles every 12 minutes (approximately Poisson in nature). The mechanic crew can service an average of 3 vehicles every 10 minutes with a repair time distribution that approximates an exponential distribution. The crew cost is approximately $150 per hour. The cost associated with lost productivity from the breakdown is estimated at $50 per hour. Which is cheaper, the existing system with one service crew or a revised system with two service crews? Note that the average waiting time for adding the second crew is 0.0

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of 3 vehicles every 12 minutes (approximately Poisson in nature). The mechanic crew can service an average of 3 vehicles every 10 minutes with a repair time distribution that approximates an exponential distribution. The crew cost is approximately $150 per hour. The cost associated with lost productivity from the breakdown is estimated at $50 per hour. Which is cheaper, the existing system with one service crew or a revised system with two service crews? Note that the average waiting time for adding the second crew is 0.0

Practical Management Science

6th Edition

ISBN:9781337406659

Author:WINSTON, Wayne L.

Publisher:WINSTON, Wayne L.

Chapter12: Queueing Models

Section12.5: Analytic Steady-state Queueing Models

Problem 9P

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A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of 3 vehicles every 12 minutes (approximately Poisson in nature). The mechanic crew can service an average of 3 vehicles every 10 minutes with a repair time distribution that approximates an exponential distribution. The crew cost is approximately $100 per hour. The cost associated with lost productivity from the breakdown is estimated at $50 per hour. Which is cheaper, the existing system with one service crew or a revised system with two service crews? Note that the average waiting time for adding the second crew is 0.02.
Virginia's Ron McPherson Electronics Corporation retains a service crew to repair machine breakdowns that occur on an average of λ = 4 per 8-hour workday (approximately Poisson in nature). The crew can service an average of µ = 6 machines per workday, with a repair time distribution that resembles the negative exponential distribution. a) The utilization rate of this service system = 0.67 (round your response to two decimal places). b) The average downtime for a broken machine = 0.50 days (round your response to two decimal places). c) The average number of machines waiting to receive service at any given time = 1.33 machines (round your response to three decimal places). d) The probability that there is more than one machine that is in the system = 0.444 (round your response to three decimal places). The probability that there are more than two machines that are in the system = 0.296 (round your response to three decimal places). The probability that there are more than three machines…
Virginia's Ron McPherson Electronics Corporation retains a service crew to repair machine breakdowns that occur on an average of λ = 2 per 8-hour workday (approximately Poisson in nature). The crew can service an average of μ = 10 machines per workday, with a repair time distribution that resembles the negative exponential distribution. a) The utilization rate of this service system = 0.200.20 (round your response to two decimal places). b) The average downtime for a broken machine = . 40.40 days (round your response to two decimal places).
Virginia's Ron McPherson Electronics Corporation retains a service crew to repair machine breakdowns that occur on an average of λ = 2 per 8-hour workday (approximately Poisson in nature). The crew can service an average of μ = 10 machines per workday, with a repair time distribution that resembles the negative exponential distribution. a) The utilization rate of this service system = 0.200.20 (round your response to two decimal places). b) The average downtime for a broken machine = 0.130.13 days (round your response to two decimal places). c) The average number of machines waiting to receive service at any given time = nothing machines (round your response to three decimal places).
Virginia's Ron McPherson Electronics Corporation retains a service crew to repair machine breakdowns that occur on an average of λ = 4 per 8-hour workday (approximately Poisson in nature). The crew can service an average of μ = 6 machines per workday, with a repair time distribution that resembles the negative exponential distribution. a) The utilization rate of this service system (round your response to two decimal places)
A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of 15 vehicles per hour (approximately Poisson in nature). The mechanic crew can service an average of 3 vehicles every 10 minutes with a repair time distribution that approximates an exponential distribution. The crew cost is approximately $100 per hour. The cost associated with lost productivity from the breakdown is estimated at $25 per vehicle per hour (or any fraction thereof). Which is cheaper, the existing system with one service crew, or a revised system with two service crews? The average waiting time for adding the second crew is 0.02.
The Bijou Theater shows vintage movies. Customers arrive at the theater line at the rate of 100 per hour. The ticket seller averages 30 seconds per customer, which includes placing validation stamps on customers’ parking lot receipts and punching their frequent watcher cards. (Because of these added services, many customers don’t get in until after the feature has started.) What is the average customer time in the system? What would be the effect on customer time in the system of having a second ticket taker doing nothing but validations and card punching, thereby cutting the average service time to 20 seconds? Would system waiting time be less than you found in (b) if a second window was opened with each server doing all three tasks?
The Bijou Theater shows vintage movies. Customers arrive at the theater line at a rate of 100 per hour. The ticket seller averages 30 seconds per customer, which includes placing validation stamps on customers’ parking lot receipts and punching their frequent watcher cards. (Because of these added services, many customers don’t get in until after the feature has started.)a. What is the average customer time in the system?b. What would be the effect on customer time in the system of having a second ticket taker doing nothing but validations and card punching, thereby cutting the average service time to 20 seconds?c. Would system waiting time be less than you found in (b) if a second window was opened with each server doing all three tasks?
The BPD has three tellers to provide service. Each teller, on average, serves one customer in three minutes per customer, the latter arriving 50 every hour. Due to complaints received, an evaluation of the system has been requested:(a) Give the average utilization of the service system with the three tellers.b) What is the probability of arriving at the bank with no one there?c) What is the average number of customers waiting in line?d) On average how long does a customer wait in line to be served?e) On average how many customers would be served at a teller and waiting in line?
During the recent pandemic, the seaport in Savannah Georgia, the third busiest in the United States, averaged loading or unloading 5.5 cargo ships per week. The average time to unload a ship is 1.95 days. Multiple cranes to load and unload the ship operate six days a week. Do not round intermediate calculations. a. How many ships are waiting to be unloaded on average using Little's Law? Round your answer up to the nearest whole number. ship(s) b. During the pandemic, at times, demand doubled, how many ships are waiting to be unloaded on average using Little's Law? Round your answer up to the nearest whole number. ship(s) C. If demand remains at 5.5 cargo ships per week and through better scheduling, training, and crane operations, the average time to unload a ship lowers to 1.05 days, how many ships are waiting? Round your answer up to the nearest whole number. ship(s)
Martin Weir is studying a waiting line for a 9 server system at Market Fresh Foods. The company wants to be sure that its customers enjoy a quality service experience. Martin has studied operations for the past 2 weeks and has determined that on average, a customer arrives every 0.0061 Minute(s) and the average service is completed in 0.0282 Minute(s). Answer the following:. Offered workload rate =
The Judy Gray Income Tax Service is analyzing its customer service operations during the month prior to the April filing deadline. On the basis of past data it has been estimated that customers arrive according to a Poisson process at a rate of 5 customers per hour. The time for Judy to complete a customer interview averages 10 minutes. (Actual resturns are completed by part-time interns hired by Judy.) Based on this information, answer the following questions: If you went to Judy, how much time would you allow for getting your return done? On average, how much room should be allowed for the waiting area? If Judy stayed in the offce 12 hours per day, how many hourg on average, per day, would she be busy? What is the probability that Judy is idle?