Part II Shining Corporation adopts the cost model as its accounting policy in subsequently measuring its depreciable assets and uses straight-line depreciation on these assets. The company records annual depreciation expense at the end of each calendar year. On 10 January 2015, the company purchased an equipment costing $90,000. The equipment's useful life was estimated to be 12 years with a residual value of $18,000. Depreciation for partial years is recorded to the nearest full month. In early January 2019, after 4 years of experience with the equipment, management decided to revise its estimated life from 12 years to 20 years. No change was made in the estimated residual value. The revised estimate of the useful life was decided prior to recording annual depreciation expense for the year ended 31 December 2019. Required: Determine the depreciation expense on 31 December 2019. Show detailed workings on depreciation expense determined from the cost of equipment. (7 marks)