Winston plc purchased a new machine on October 1, 2018, at a cost of 120,000. The company estimated that the machine will have a residual value of 12,000. The machine is expected to be used for 12,000 working hours during its 4-year life. Instructions Compute the depreciation expense under the following methods for the year indicated. (a) Straight-line for 2018. (b) Units-of-activity for 2018, assuming machine usage was 1,700 hours. (c) Declining-balance using double the straight-line rate for 2018 and 2019