On July 1, 2019, Caterpillar Inc. bought the equipment at $80,000. At the time of the purchase, the residual value was estimated at $5,000 and the useful life was estimated to be 5 years. On Mar 31, 2021, the company sold the equipment and received $30,000 cash. The company has a December 31 year-end.

Assume that the company uses the double-diminishing-balance method for the depreciation of this equipment, how much is the depreciation expense for the year 2020? Assume that the company uses the straight-line depreciation method for this equipment, (1) how much is the gain or loss from the disposal of this equipment on Mar 31, 2021? (2) Prepare the journal entry to record the depreciation expense for 2021 and record the sale of equipment on Mar 31, 2021. Assume that the company uses the straight-line depreciation method for this equipment. Also assume that on Jan 1 of 2020, the company changed the estimation of the useful life and then realized that the only 2 years are left in terms of the useful life from Jan. 1 of 2020. The residual value estimation did not change at that time. How much is the depreciation expense for the year 2020?