Henderson Company uses the retail inventory method to estimate ending inventory and cost of goods sold. The following data are available from Henderson's accounting records. Cost Retail Beginning Inventory $336,000 $480,000 Net purchases $852,000 $1,200,000 Freight-in. Net Mark-ups $50,000 Net Mark-downs Sales $30,000 $30,000 $1,200,000 a. Estimate Henderson's ending inventory and cost of goods sold for the year using the average cost retail method. b. Estimate Henderson's ending inventory and cost of goods sold for the year using the conventional retail method