Final answer:
According to the lower of cost or market rule, A1 Electronics should use $18 as the unit value for its ending inventory, which represents the replacement cost that is lower than the cost per unit.
Step-by-step explanation:
The student's question relates to which unit value A1 Electronics should use when applying the lower of cost or market (LCM) rule to ending inventory. The cost per unit is $20, the replacement cost is $18, the selling price is $30, and the selling costs are $4.
Considering the normal profit margin is 30% of the selling price, which is $9 ($30 * 30%), we can determine the market value to be the replacement cost since it needs to be lower than the ceiling (selling price minus selling costs, which is $26) and higher than the floor (selling price minus selling costs minus normal profit, which is $17).
Therefore, according to the LCM rule, the inventory should be valued at $18 per unit, which is the replacement cost, as it is lower than the cost per unit.