申論題

6.(20 points) Marie is running a small mobile shop and now selling the very popular ePhone. In such a small town, the daily demand for ePhone is limited and following a probability distribution shown in the table below. Since the shop is with a little capital, Marie can keep at most 2 cPhoncs in inventory every day. When the inventory lcvel is low at the end of the day, she makes an order to the phone suppliers. Assuming the replenishment is instant, i.e, when Marie makes the order at the end of today, the ordered phone(s) will arrive at the beginning of tomorrow. There are two types of costs associated with each order: the fixed cost of 400 NTD for the truck; the variable cost of 100 NTD/phone. The holding cost for an unsold phone in the inventory is 100 NTD. If the demand exceeds the available phones in inve entory during the day, the backordered cost is incurred with the penalty of 1000 NTD per phone.

(b) (10 points) Find and demonstrate a better ordering policy than the one Marie uses, ie., the policy with a lower cost.