Porter Inc. acquired a machine that cost $720,000 on October 1, 2019. 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 uses the calendar year for financial reporting. Depreciation expense for one-fourth of a year was recorded in 2019.

Required:

a. Using the straight-line depreciation method, calculate the depreciation expense to be recognized in the income statement for the year ended December 31, 2021, and the balance of the Accumulated Depreciation account as of December 31, 2021. This is the third calendar year in which the asset has been used.

b. Using the double-declining-balance depreciation method, calculate the depreciation expense for the year ended December 31, 2021, and the net book value of the machine at that date.