Mayhew AG has the following inventory, purchases, and sales data for the month of March. The physical inventory count on March 31 shows 500 units on hand. Instructions a. Under a periodic inventory system, determine the cost of inventory on hand at March 31 and the cost of goods sold for March under (1) FIFO and (2) average-cost. b. Under a perpetual inventory system, determine the cost of inventory on hand at March 31 and the cost of goods sold for March under (1) FIFO and (2) average-cost