Note: Please explained clearly how you calculate the answer. Thank you!

Required: 1. Assuming that CNB uses a periodic inventory system and employs the average cost method, determine cost of goods sold for September and September's ending inventory. 2. Assuming that CNB uses a perpetual inventory system and employs the average cost method, determine cost of goods sold for September and September's ending inventory. Assuming that CNB uses a periodic inventory system and employs the average cost method, determine cost of goods sold for September and September's ending inventory. (Round cost per unit to 2 decimal places.) Assuming that CNB uses a perpetual inventory system and employs the average cost method, determine cost of goods sold for September and September's ending inventory. (Enter inventory reductions for sales with a minus sign. Round cost per unit to 2 decimal places.)