MGT 3121- Midterm Review Questions

It takes a barber 10 minutes to serve one customer. What is the capacity of the barber expressed in customers per hour?

6 customers per hour 60/10= 6

Consider a process consisting of three resources. Assume there exists unlimited demand for the product. -Resource 1 has a processing time of 10 minutes per unit. -Resource 2 has a processing time of 8 minutes per unit. -Resource 3 has a processing time of 7 minutes per unit. The three resources are staffed by different workers individually. The flow diagram is shown above. What is the capacity of resource 2?

0.125 units per minute Capacity= 1/ Processing Time 1/8= 0.125

It takes a barber 10 minutes to serve one customer. Assuming the demand for the barber is 1 customers per hour, what is the flow rate?

1 customer per hour Flow Rate= Min( 1, 6)

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. If one additional worker could be hired, to which resource should the additional resources be assigned? Calculate the process capacity

10 units per hour Add the worker to resource 1. Resource 3 is the new bottleneck with capacity 60 min/hr / 6 min per unit = 10.0 units per hour.

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. If they could take 1 minute of task time from one resource and give it to another resource (so the labor content remains the same), What would be the new capacity of the process (units per hour)? Assume that there is still only 1 worker per station.

10 units per hour Take 1 minute away from Resource 1 and give it to Resource 2. Resources 1 and 3 are now the bottlenecks with capacity 10.0 units per hour (see part f).

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. What would be the capacity of the process if they integrated the work so that all workers do all three tasks (units per hour)? Assume that there is still only 1 worker per station.

10.6 units per hour Total processing time is 7 + 4 + 6 = 17 minutes. Capacity = 3 workers × 60 min/hr / 17 min per unit = 10.6 units per hour.

Bikes enter a warehouse at the rate of 630 bikes per month. On average, a bike spends 19 months in the warehouse. On average, how many bikes are in the warehouse?

11,970 bikes Use Little's Law, I = R × T. Hence, I = 630 × 19 = 11,970

Max Stamp approves study abroad documents for the university. Students must wait in line with their forms outside Max's office. One student at a time is allowed in his office and Max takes precisely 10 minutes to evaluate each student's set of documents. On average, 5 students per hour go to his office and they spend, on average, 150 minutes trying to get their forms approved (time waiting in queue plus time in Max's office having him evaluate their documents) On average, how many students are waiting outside of Max's office?

11.7 Time in queue = 150 − 10 = 140 min. Interarrival time = 12 min. The average number of customers waiting in the queue = Time in queue / Interarrival time = 140 / 12 = 11.7.

A community health system's nurse team consists of 12 nurses working in the local community. It takes a nurse 0.75 hours to complete one patient visit (including travel time and breaks). Nurses work 9 hours per workday. What is the capacity of the nurse team over the course of a 9-hour workday?

144 visits per 9 hour workday 12 nurses × 9 hours / 0.75 hours per visit = 144.0 visits

It takes a barber 10 minutes to serve one customer. Assuming the demand for the barber is 1 customers per hour, what is the utilization?

16.67 percent 1 demand / 6 capacity = 16.67%

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. What is the labor content?

17 minutes per unit Labor content = 7 minutes Resource 1 + 4 minutes Resource 2 + 6 minutes Resource 3 = 17 minutes

Consider a process consisting of three resources. Assume there exists unlimited demand for the product. -Resource 1 has a processing time of 10 minutes per unit. -Resource 2 has a processing time of 8 minutes per unit. -Resource 3 has a processing time of 7 minutes per unit. The three resources are staffed by different workers individually. The flow diagram is shown above. How long does it take the process to produce 205 units starting with an empty system, assuming this is a worker-paced process?

2,065 minutes (205 units × 10 minutes) + 8 minutes + 7 minutes = 2065 minutes.

People are served in a process with two resources. The first resource has a capacity of 2 people per minute. The capacity of the second resource is 1.8 people per minute. The first resource has 6 workers and the second resource has 8 workers. One additional worker is hired who is as productive as the current workers. What is the new capacity of this process?

2.000 (1.8 / 8) × (8 + 1) = 2.025 With 1.8 units per minute, the second is the bottleneck in the revised system. The capacity of the system is the capacity of this bottleneck 2.000 people per minute.

Boats enter a harbor at the rate of 15 boats per day. There are on average 38 boats in the harbor. On average, how long does a boat spend in the harbor?

2.533 days Use Little's Law, T = I / R. Hence, T = 38 / 15 = 2.533

An automated car wash serves customers with the following serial process: pretreat, wash, rinse, wax, hand dry. Each of these steps is performed by a dedicated machine except for the hand-dry step, which is performed manually on each car by one of three workers. The steps of the process have the following processing times: Pretreat: 2 minute per car Wash: 7 minutes per car Rinse: 1 minutes per car Wax: 4 minutes per car Hand dry: 6 minutes per car If the car wash has a demand of 8 cars per hour, what is the utilization of hand dry?

26.67 % The flow rate is 8 cars per hour and the capacity of hand dry is 30 cars per hour. So utilization is 8 / 30 = 26.67%

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. Assume the demand rate is 20 units per hour. What is the takt time?

3 minutes per unit Takt Time = 1/Demand rate = 1/(20 customers/60 minutes) = 3.00 minutes

At the stadium, there are eight lines for arriving customers, each staffed by a single worker. The arrival rate for customers is 190 per minute and each customer takes (on average) 2 seconds for a worker to process. The coefficient of variation for arrival time is 1.2 and the coefficient of variation for service time is 1.5. On average, how many customers will be waiting in the queue?

3.287 Customers Interarrival time (a) = 60 seconds per minute / 190 customers per minute = 0.316 seconds. Utilization = p / (a × m) = 2 / (0.316 × 8) = 0.792. Number in queue = Tq / a = 1.038 / 0.316 = 3.287 customers.

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. What is the cost of direct labor?

4.55 per unit Resource 1 is the bottleneck center at 7 minutes per unit. The Direct Labor cost is (7 minutes per resource × 3 resource centers/60 minutes per hour) × $13 per hour = $4.55

A community health system's nurse team consists of 12 nurses working in the local community. It takes a nurse 0.75 hours to complete one patient visit (including travel time and breaks). Nurses work 9 hours per workday. Assuming the demand for the nurses is 60 patients per day, what is the utilization of the nurse team?

42 % 60 demand / 144.0 capacity = 42% utilization.

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. Assume the demand rate is 20 units per hour. What is the target manpower?

5.67 employees The target manpower = 17 Labor content/3.00 minutes Takt time = 5.67

CPU-on-Demand (CPUD) offers real-time high-performance computing services. CPUD owns 1 supercomputer that can be accessed through the Internet. Their customers send jobs that arrive, on average, every 6 hours. The standard deviation of the interarrival times is 7 hours. Executing each job takes, on average, 3 hours on the supercomputer. What is the utilization (as a percent) of CPUD's supercomputer?

50 % Utilization = Processing time / Interarrival time = 3 / 6 = 0.50 = 50.00%.

The average time to serve a customer at a fast-food restaurant is 5 minutes. The standard deviation of the service time is 4 minutes. What is the coefficient of variation of the service time? a. 5 b. 4 c. 1.25 d. 0.8

d. 0.8 CVp= Standard Deviation / Average CVp= 4/5 = 0.8

An automated car wash serves customers with the following serial process: pretreat, wash, rinse, wax, hand dry. Each of these steps is performed by a dedicated machine except for the hand-dry step, which is performed manually on each car by one of three workers. The steps of the process have the following processing times: Pretreat: 2 minute per car Wash: 7 minutes per car Rinse: 1 minutes per car Wax: 4 minutes per car Hand dry: 6 minutes per car If the car wash has a demand of 14 cars per hour, what is the utilization of the machine that performs the Wax process?

57.13 % Utilization is the flow rate divided by the capacity of the process step. If the demand is 14 cars per hour, the flow rate is 8.57 cars per hour, because the flow rate is the minimum of the capacity of the bottleneck and the demand. The capacity of the machine that performs the Wax process is 1 / 4 × 60 = 15 cars per hour. The utilization of this machine is 8.57 / 15 = 57.13%.

The organizers of a conference in the Houston Convention Center are evaluating the possibility of setting up a computer area where attendees can check their e-mail on computers provided by the organization. There will be one common queue for all computers and only one person uses a computer at a time. On average, there are 20 attendee arrivals per hour and the average time a person spends on the computer is 15 minutes. To ensure that waiting times are not too long, the organizers want to ensure that the utilization of the computers doesn't exceed 90 percent. At least how many computers do they need to have?

6 Computers Utilization = p / (a × m), so 0.90 = (15) / (3 × m) And solve for m. m = 5.556, which rounds up to 6 computers.

It takes a barber 10 minutes to serve one customer. Assuming the demand for the barber is 1 customers per hour, what is the utilization?

60 minutes per customer Cycle time = 1/flow rate 1/60 minutes = 60.00 minutes per customer

An automated car wash serves customers with the following serial process: pretreat, wash, rinse, wax, hand dry. Each of these steps is performed by a dedicated machine except for the hand-dry step, which is performed manually on each car by one of three workers. The steps of the process have the following processing times: Pretreat: 2 minute per car Wash: 7 minutes per car Rinse: 1 minutes per car Wax: 4 minutes per car Hand dry: 6 minutes per car Now assume demand is 14 cars per hour. Starting from an empty system (and assuming the stations can work independently), how long would it take (minutes) to wash 8 cars?

69 minutes The first unit requires 2 + 7 + 1 + 4 + 6 = 20 minutes. The other 7 require 7 × 7 minutes = 49 minutes. Total time is 20 + 49 = 69 minutes.

CPU-on-Demand (CPUD) offers real-time high-performance computing services. CPUD owns 1 supercomputer that can be accessed through the Internet. Their customers send jobs that arrive, on average, every 7 hours. The standard deviation of the interarrival times is 7 hours. Executing each job takes, on average, 3 hours on the supercomputer and the standard deviation of the processing time is 5.0 hours. How long does a customer have to wait to have a job completed?

7.3 hours Tq= p x (Utilization/ ( 1- Utilization) x (CVa^2 + CVp^2)/ (2) =(3 + 3 )x ((3/7) / (1 - 3/7) x (1^2 + (5/3)^2) / 2 => 3 x .75 x 1.89= 4.25 hours + 3= 7.25

An automated car wash serves customers with the following serial process: pretreat, wash, rinse, wax, hand dry. Each of these steps is performed by a dedicated machine except for the hand-dry step, which is performed manually on each car by one of three workers. The steps of the process have the following processing times: Pretreat: 2 minute per car Wash: 7 minutes per car Rinse: 1 minutes per car Wax: 4 minutes per car Hand dry: 6 minutes per car If the car wash has a demand of 8 cars per hour, what is the cycle time of the process (minutes)?

7.50 minutes The process is demand constrained, so the flow rate is 8 cars per hour. The cycle time is 1 / 8 hours, or 60 / 8 = 7.50 minutes

An automated car wash serves customers with the following serial process: pretreat, wash, rinse, wax, hand dry. Each of these steps is performed by a dedicated machine except for the hand-dry step, which is performed manually on each car by one of three workers. The steps of the process have the following processing times: Pretreat: 2 minute per car Wash: 7 minutes per car Rinse: 1 minutes per car Wax: 4 minutes per car Hand dry: 6 minutes per car If the car wash has a demand of 14 cars per hour, what is the flow rate of the process?

8.57 customers per hour The bottleneck is the Wash process, with a capacity of 8.57 cars per hour. The flow rate is the minimum of the capacity of the bottleneck and the demand.

Consider a process consisting of three resources. Assume there exists unlimited demand for the product. -Resource 1 has a processing time of 10 minutes per unit. -Resource 2 has a processing time of 8 minutes per unit. -Resource 3 has a processing time of 7 minutes per unit. The three resources are staffed by different workers individually. The flow diagram is shown above. What is the utilization of resource 2?

80% Flow rate = 60/10 = 6.000 units/hour. Resource 2 capacity = 60/8 = 7.500 units/hour. Resource 2 Utilization = Flow Rate / Capacity = 6.000/7.500 = 80%.

Consider a process consisting of three resources. Assume there exists unlimited demand for the product, and that all activities are always performed in the following sequence. Resource 1 has a processing time of 7 minutes per unit. Resource 2 has a processing time of 4 minutes per unit. Resource 3 has a processing time of 6 minutes per unit. All three resources are staffed by one worker and each worker gets paid $13 per hour. What is the average labor utilization?

80.95 % Labor Utilization = 17 labor content/21 capacity = 80.95%

A community health system's nurse team consists of 12 nurses working in the local community. It takes a nurse 0.75 hours to complete one patient visit (including travel time and breaks). Nurses work 9 hours per workday. Assuming the demand for the nurses is 60 patients per day, what is the cycle time?

9 minutes per patient (9 hours × 60 minutes) / 60 patients = 9.0 minutes per patient

For the purpose of process analysis, what is NOT an appropriate flow unit to analyze the operation of a hair salon? a. Number of customers served per day b. Monthly sales figures c. The dollar value of haircare products sold per day d. Number of stylists working each day

d. Number of stylists working each day

Experience the Tour de France (ETF) is a specialty travel agent. It arranges vacations for amateur cyclists who want to experience the Tour de France by riding through one or more stages in the race. It has three people who take calls from clients. Each call lasts on average 20 minutes, with a standard deviation of 60 minutes. A call arrives on average every 15 minutes with a standard deviation of 15 minutes. On average, how many minutes does a caller wait before talking to an agent?

=13.62 - We are given the interarrival time (a = 15 min), service time (p = 20 min), number of servers (m = 3 people), standard deviation of interarrival time (15 min) and standard deviation of service time (60 min). - Therefore, the coefficient of variation of arrival times is 15 / 15 = 1 and the coefficient of variation of service times is 60 / 20 = 3. Moreover, the utilization is 20 / (15 x 3) = 0.4444. Therefore, the average time in the queue is 6.6667 x 0.4086 x 5.0 = 13.6211 minutes, or 13.62 minutes rounded to two decimals

_________ means to detect and address defects when and where they occur and prevent them from recurring. a. Just-In-Time b. Built-in quality c. Process Improvement D. Stable Environment

B. Built-in quality

Twenty new members are elected to an agency every two years. The agency has 100 members on average overall. How long does a member hold his/her position at the agency? a. 50 years b. 20 years c. 10 years d. 5 years

C. 10 years Inventory = 100 members. Flow rate = 20/2 = 10 new members per year. I = R × T, therefore T = I/R. Flow time = 100/10 = 10 years.

C&A uses a line of 5 stations to make a product. The cycle time is 30 seconds per unit. The inventory between stations is 10 units. Inspection happens at the end of the process. Which of the following is NOT a way to shorten the information turnaround time for a defect made at station 2? a. Reduce the amount of inventory between stations. b. Reduce cycle time c. Inspect at every station d. Add another station after station 2

D. Add another station after station 2

Consider a process consisting of three resources. Assume there exists unlimited demand for the product. -Resource 1 has a processing time of 10 minutes per unit. -Resource 2 has a processing time of 8 minutes per unit. -Resource 3 has a processing time of 7 minutes per unit. The three resources are staffed by different workers individually. The flow diagram is shown above. What is the bottleneck in the process?

Resource 1 -The bottleneck is the resource with the smallest capacity.

An automated car wash serves customers with the following serial process: pretreat, wash, rinse, wax, hand dry. Each of these steps is performed by a dedicated machine except for the hand-dry step, which is performed manually on each car by one of three workers. The steps of the process have the following processing times: Pretreat: 2 minute per car Wash: 7 minutes per car Rinse: 1 minutes per car Wax: 4 minutes per car Hand dry: 6 minutes per car Which resource is the bottleneck of this process?

Wash Wash has the lowest capacity

A firm invents an app that allows customers to make purchases with their smartphone. The firm hopes its new mobile payment app will __________ the efficient frontier through __________. a. shift, innovation b. stay on, innovation c. stay on, imitation d. shift, imitation

a. shift, innovation

Which of the following is a reason why queues will form even if capacity exceeds demand? a. There is no variability in average capacity. b. Customers do not arrive in a consistent pattern. c. Customers arrive in a consistent pattern. d. There is no variability in the arrival of customers.

b. Customers do not arrive in a consistent pattern.

There are four hotels competing with otherwise very similar products on the dimensions of price ($ per night) and amenities (measured by the number of *s awarded by customer reviews). Which of these hotels are on the efficient frontier? a. Hotel A: price = $200 per night; rating: *** b. Hotel B: price = $150 per night; rating: **** c. Hotel C: price = $300 per night; rating ***** d. Hotel D: price = $80 per night; rating **

b. Hotel B: price = $150 per night; rating: **** c. Hotel C: price = $300 per night; rating ***** d. Hotel D: price = $80 per night; rating **

Which of the following statements about takt time and cycle time is TRUE? a. If takt time is longer than cycle time, target manpower will be higher than current staff level. b. If takt time is longer than cycle time, target manpower will be lower than current staff level. c. Supply matches demand when takt time is shorter than cycle time. d. Supply is less than demand when takt time is equal to cycle time.

b. If takt time is longer than cycle time, target manpower will be lower than current staff level.

Line balancing is the act of allocating activities of a process across the process resources as __________ as possible so that all resources have a comparable __________. a. irregularly, inventory level b. evenly, utilization level c. irregularly, utilization level d. evenly, inventory level

b. evenly, utilization level

Flow rate tells us __________. a. how much stuff is in the process b. how much stuff moves through the process per time unit c. how much time stuff spends in the process d. how much stuff is needed for the process

b. how much stuff moves through the process per time unit

Which of the following statements about takt time is FALSE? a. Takt time is the ratio between the available time and the required production quantity. b. Takt time is dependent on the required quantity of output. c. Takt time tells us how much time actually elapses between completing two consecutive units. d. Takt time tells us how much time should elapse between completing two consecutive units.

c. Takt time tells us how much time actually elapses between completing two consecutive units.

If __________ is the constraint, we should __________ the staffing level to raise capacity. a. demand, lower b. demand, raise c. capacity, raise d. capacity, lower

c. capacity, raise

An example of a flow unit at a fast-food restaurant is the __________. a. cashiers b. kitchen c. customers d. suppliers

c. customers