Grove Co. acquired a production machine on January 1, 2019, at a cost of $485,000. The machine is expected to have a four-year useful life, with a salvage value of $82,000. The machine is capable of producing 52,000 units of product in its lifetime. Actual production was as follows: 11,440 units in 2019; 16,640 units in 2020; 14,560 units in 2021; 9,360 units in 2022.

Following is the comparative balance sheet presentation of the net book value of the production machine at December 31 for each year of the assets life, using three alternative depreciation methods (items ac):

Required:

Identify the depreciation method used for each of the following comparative balance sheet presentations (items ac). If a declining-balance method is used, be sure to indicate the percentage (150% or 200%). (Hint: Read the balance sheet from right to left to determine how much has been depreciated each year. Remember that December 31, 2019, is the end of the first year.)

Production Machine, Net of Accumulated Depreciation
		At December 31
	Depreciation Method	2022	2021	2020	2019
a.		82,000	154,540	267,380	396,340
b.		82,000	82,000	121,250	242,500
c.		82,000	182,750	283,500	384,250