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 $20 each. Purchases on December 7 Purchases on December 14 10 units @ $ 6 cost 20 units @ $12 cost Purchases on December 21 15 units @ $14 cost Determine the costs assigned to ending inventory when costs are assigned based on the LIFO method.