Amortization of Patent

On December 31, it was estimated that goodwill of $750,000 was impaired. In addition, a patent with an estimated useful economic life of 18 years was acquired for $864,000 on August 1.

Journalize the adjusting entry on December 31 for the amortization of the patent rights.

Dec 31 Amortization Expense-Patents??
Patents??


I've tried 28000 ((864000/18) * (7/12)) and 32000 ((864000/18) * (8/12)) and neither one of these answers seem to be correct.

You need to calculate the number of months in use as of December 31. From August to December it is 5 months. Hence:

864,000/18 = 48,000 per year and
48,000/12 = 4,000 per month
The amortization will be 4,000 x 5 = 20,000