Suppose that a company offers quantity discounts. If up to a 1000 units are purchased, the unit price is $10; if more than a thousand and up to 5000 units are purchased, the unit price is $9; and if more than 5000 units are purchased, the unit price is $7.50. Develop a spread sheet using the VLOOKUP function to find the unit price associated with any order quantity and compute the total cost of the order.