4. ST Inc. purchased an equipment on Jan 1, 2016 costing $ 40,000 with a five-year useful life and an estimated salvage value of AED 2,000. The Company uses straight method of depreciation. At the beginning of the third year, ST determines that the machine has four more years of remaining useful life, after which it will have an estimated $1,500 salvage value.

Calculate the amount of depreciation for each of the final four years given the revised estimates.