I need detailed help with steps on how the $8,400 GAAP loss on Inventory was calculated exactly and also how the $3,000 was calculated exactly.

The following information pertains to inventory held by a company on December 31, 2013 :

Historical Cost : $30,000

Replacement Cost : $20,000

Net Realizable Value : $27,000

Normal Profit Margin : 20%

Question : As a result of inventory loss, what is the difference in reporting using US GAAP and IFRS?

Solution Given : $8,400 loss on inventory from Lower of Cost Or Market minus $3,000 IFRS Loss on Inventory from LCM = $5,400 higher income under IFRS