（英语）
Your business buys 36,500 litres of calcium sulphate each year.You could order it all at once,but then you would need to rent storage space for it,and that costs $1 per litre.You could,every day,put in an order for 100 litres—that would reduce your storage costs to $100,but every time you put in an order you have to pay a $14.60 processing fee.How often should you order,and how much,to minimize the total of your ordering and storage costs?