Gibson Company had the following property, plant and equipment purchases during 2020: (1) On June 8, equipment costing $200,000 with a 10-year service life and an estimated $10,000 residual value was purchased. The equipment is rated to produce 100,000 units over its service life. The equipment produced 11,600 units in 2020 and 21,000 units in 2021. 93 94 (2) On November 2, a machine costing $500,000 with a 10-year service life and an estimated $50,000 residual value was purchased. The 95 machine is rated to produce 200,000 units over its service life. The machine produced 1,500 units in 2020 and 19,000 units in 2021. 96 97 98 Required: 99 100 Assuming Gibson Company has a December 31 year end, prepare the necessary adjusting journal entries at December 31, 2020 and December 31, 2021 to record depreciation under the following depreciation methods (using the nearest whole month method): 201 202 203 (a) Units of Production. 204 205 (b) Double-declining-balance. 206 207