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Required information [The following information applies to the questions displayed below.] 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 $39 each. Of the units sold, eight are from the December 7 purchase and seven are from the December 14 purchase. Determine the costs assigned to ending inventory when costs are assigned based on specific identification