Periodic inventory by three methods The beginning inventory for Midnight Supplies and data on purchases and sales for a three-month period are shown below: 1. Determine the inventory on March 31 and the cost of goods sold for the three-month period, using the first-in, first-out method and the periodic inventory system. 2. Determine the inventory on March 31 and the cost of goods sold for the three-month period, using the last-in, first-out method and the periodic inventory system. Inventory, March 31 $ 1. Determine the inventory on March 31 and the cost of goods sold for the three-month period, using the first-in, first-out method and the periodic inventory system. 2. Determine the inventory on March 31 and the cost of goods sold for the three-month period, using the last-in, first-out method and the periodic inventory system. 3. Determine the inventory on Marth 31 and the cost of goods sold for the three-month period, using the weighted average cost method and the periodic inventory system. Round the weighted average unit cost to the nearest cent. 4. Compare the gross profit and the March 31 inventories, using the following column headings, For those boxes in which you must enter subtracted or negative numbers use a minus sign. in