Tops Ltd purchased a new machine on 1 October 2015 at a cost of $230000. The entity estimated that the machine has a residual value of $30000. The machine is expected to be used for 40,000 working hours during its 10 year life. Assume a 31 December year-end. Required a) Calculate the depreciation expense using the straight-line method for 2015 and 2016. b) Calculate the depreciation expense using the diminishing-balance method using a depreciation rate of 20% for 2015 and 2016. c) Calculate the depreciation expense using the units-of-production method for 2015, assuming the machine usage was 1960 hours