Trey Monson starts a merchandising business on December 1 and enters into the following three inventory purchases. Monson uses a perpetual inventory system. Also, on December 15, Monson sells 15 units for $36 each. Purchases on December 7 Purchases on December 14 Purchases on December 21 10 units @ $22.00 cost 20 units @ $28.00 cost 15 units @ $30.00 cost termine the costs assigned to ending inventory when costs are assigned based on the weighted average method. te: Round your per unit costs to 2 decimal places. ecember 7 Weighted Average Perpetual: Goods purchased Cost of Goods Sold Inventory Balance Date # of units Cost per unit Inventory Value # of units sold Cost per Cost of Goods unit # of units Sold Cost per unit Inventory Balance $ 0.00 $ 0.00 ecember 14 erage cost December 14 cember 15 cember 21 erage cost December 21 als $ 0.00 $ 0.00 0 $ 0.00 $ 0.00