5.6.The demand of an item is uniform at a rate of 20 units per month. The fixed cost is Rs. 10 each time a production run is made. The production cost is Rs. 1 per item and the inventory carrying cost is Rs.0.25 per item per month. If the shortage cost is Rs.1.25 per item per month. Determine how often to make a production run and of what size it should be