Required information Trey Monson starts a merchandising business on December 1 and enters into the following three inventory purchases. Also, on December 15, Monson sells 28 units for $10 each. Purchases on December 7 18 units @ $4.00 cost Purchases on December 14 35 units @ $6.00 cost Purchases on December 21 28 units @ $7.00 cost Required: Monson sells 28 units for $10 each on December 15. Of the units sold, 14 are from the December 7 purchase and 14 are from the December 14 purchase. Monson uses a perpetual inventory system. Determine the costs assigned to the December 31 ending inventory when costs are assigned based on specific identification.