Fixed assets are impaired how to depreciate it, according to the remaining useful life of depreciation?

The fixed assets from July 2008 to start depreciation, to December 2009 has been depreciated for 1.5 years, the remaining depreciable life of 8.5 years, the book value of the fixed assets 55-13 = 420,000 yuan, 2010 depreciation = (42-8)/8.5 = 40,000 yuan