Solution :
The net operating income under absorption costing.
Sales (3000 x $ 90) $ 2,70,000
Less : The cost of the goods sold (3000 x $ 81) $ 2,43,000
Gross margin $ 27,000
Less : The selling general and the administrative $ 15,000
expenses (3000 + 12000)
Net operating income $ 12,000 (loss)