Question 1 -- 2016, Capacity Planning

Question 1:A service facility has 6 workstations as ws1, ws2, ws3, ws4, ws5 and ws6. The outputs of ws1 and ws2 are required in the ratio of 2:3 in ws3 to get 5 units of output of ws3. Similarly, the outputs of ws3, ws4 and ws5 are required in the ratio of 4:2:3 in ws6 to get 9 units of output at ws6.

Capacities of these workstations are given as 3000, 4200, 7800, 3200, 5000 and 16000 units/ day respectively.

a)      What is the capacity of this complete service facility?                                         6 marks

b)      How much surplus capacity is available at each of the workstations?                 3 marks

c)      If you are allowed to increase the capacity of any one service station so that overall capacity increases, which service station you will choose for this?                     1 marks

Answers can be viewed and downloaded from https://drive.google.com/file/d/0B6PHuk6I5SxbN3ozb00wV3pvdkE/view?usp=sharing. 

Question 2 - 2016, Sequencing Rules

Question 2:A service provider charges for his service on per minute basis and the customers have to buy the service time in advance. 8 customers have bought the service time as 12, 8, 5, 16, 10, 14, 7 and 5 minutes respectively. They arrive at the service provider at different times. Their arrival time are 10, 18, 20, 23, 27, 40, 45 and 48 minutes after opening of the office.

a)      Find the average time customers spend in the system if First Come First Serve (FCFS) sequencing rule is applied.                                                                                   3 marks

b)      What will be the impact on this average time if the sequencing rule is changed to Shortest Service Time First?                                                                                              4 marks

c)      Suppose the service provider creates facilities for self-service 3 minutes of the service time requirement. It means that a customer will require to be in queue only for service time bought minus 3 minutes. For example, the customer who has bought 16 minutes of service time will self-serve for 3 minutes and wait to be served for remaining 13 minutes. What will be the impact of this change on the average time customers remain at the service facility? Assume FCFS sequencing rule for this part of the question.    3 marks

Answers can be viewed and downloaded from https://drive.google.com/file/d/0B6PHuk6I5SxbVmdLNTdyVzQ1czQ/view?usp=sharing. 

Question 3 -- 2016, Inventory Control

Question 3: Assume a single item deterministic situation with constant demand and lead time.

a)      Derive a formula for finding Economic Order Quantity (EOQ).                     2 marks

b)      For an order quantity Q1, the total ordering cost is X and inventory carrying cost is Y. X is less than Y. If we change the order quantity to Q2, total ordering cost X gets reduced. Which is closer to EOQ; Q1 or Q2? Why?                                                     3 marks

 Answer video can be viewed and downloaded from https://drive.google.com/file/d/0B6PHuk6I5SxbODhITFhfMnM3M3M/view?usp=sharing.