3. (Q, r) model question: One part company uses has monthly demand of 150 units per month. The unit cost c of the part is 3500TL. The firm uses a monthly interest rate of 2% (What is the holding cost h per month?) It takes 10 days to receive a production or the for the part. Cost of time and materials to complete a production order A is 350TL. The monthly cost of a backorder is 250TL and cost for stockout is 100TL. Demand can be approximated by Poisson distribution. Calculate the Q and r values using both the backorder cost and stockout cost approach