Porter, Inc., acquired a machine that cost $720,000 on October 1, 2010. The machine is expected to have a four-year useful life and an estimated salvage value of $80,000 at the end of its life. Porter, Inc., uses the calendar year for financial reporting. Depreciation expense for one-fourth of a year was recorded in 2010.
Using the double-declining-balance depreciation method, calculate the depreciation expense for the year ended December 31, 2012, and the net book value of the machine at that date.