THK Flight School has three contractor spare parts manufacturing company in Europe: ABC Company supplies Q family of spare parts, XYZ Company supplies Z family of spare parts and PRS Company supplies W family of spare parts. XYZ has a supply source in IZMIT that delivers Z1 semi-product for TL200. Weekly demand for Z1 is a normally distributed with a mean of 5000 and a standard deviation of 300 . The lead time required by the supplier is normally distributed with a mean of 4 weeks and a standard deviation of 2 weeks. Another company in Bursa has offered to deliver Z1s with a lead time of one week at a cost of TL 220. XYZ has a holding cost of 18 percent and targets a "cycle service level of 95 percent". The monthly demand for Qs is 40000 units, for Zs is 20000 whereas that for Ws is 80000. Qs cost the company TL800, Zs cost TL 600, and Ws cost TL 200 and the company has a holding cost of 12 percent. 2 Now, THK Flight School has to place separate orders with ABC, XYZ, and PRS and receive separate shipments. The fixed cost of each shipment is TL30,000. In the case of combining orders TL900 of cost is added to the fixed cost for each. a. Calculate the "demand uncertainty of the XYZ company for semi-product Z1". Comment on the result. b. Should XYZ company accept the offer of the company which is located in Bursa? c. What is the optimal order size and order frequency with each of the companies? d. The company thinks of combining all parts with the same contract manufacturer. This will allow for a single shipment of all products from Europe. What is the optimal order frequency and order size from the combined orders? e. What is the optimal order frequency and order size form a tailored aggregation? f. How much reduction in cycle inventory can the company expect as a result of these alternatives