On January 1, 2021, Canseco Plumbing Fixtures purchased equipment for $64,000. Residual value at the end of an estimated four-year service life is expected to be $10,000. The company expects the equipment to operate for 10,000 hours. The equipment operated for 3,900 and 4,700 hours in 2021 and 2022, respectively.

Required: a. Calculate depreciation expense for 2021 and 2022 using straight line method. b. Calculate depreciation expense for 2021 and 2022 using double-declining balance method. c. Calculate depreciation expense for 2021 and 2022 using units-of-production using hours operated.