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 $23 each. letermine the costs assigned to ending inventory when costs are assigned based on the weighted average method. lote: Round your per unit costs to 2 decimal places