A store orders 800 units of a product every 4 months. If the product is steadily depleted to 0 by the end of each 4 months, the inventory on hand I at any time t during the year is shown in the figure to the right. What is the average number of units on hand for a 4-month period? 800 Inventory (units on hand) 4 8 12 16 t Time (months) Write an inventory function (assume that it is continuous) for the first 4 months. [The graph is a straight line joining (0,800) and (4,0).] The inventory function for the first 4 months is | =