The amount that should be reported on the balance sheet for each unit in inventory is $18.
Since
Cost of inventory to purchased an item = $20
The selling price of an item = $30
Replacement cost = $18
Based on the above information, the amount that should be reported on the balance sheet is the cost of inventory or market value which ever is lower.
As we can see that the replacement cost is less than the cost of inventory so the same is to be reported.
Therefore we ignored the selling price of an item.
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