16. A shopkeeper has a uniform demand of an item at the rate of 50 units per month. He buys the item from the supplier at the cost of Rs 6 per unit and the cost of placing an order is Rs 10 every time. If the stock holding cost is 20% p.a. of the stock value, how frequently should he replenish his stock? Further, suppose the supplier offers a 5% discount on orders between 200 units and 999 units of the item and a discount of 10% on the orders exceeding or equal to 1,000 units. Is it advisable for the shopkeeper to avail either of these discount offers? (MIB, Delhi, 2008)