Smart Enterprise bought a machine costing $40,000 on 1 January 2015. The machine has a useful life of 4 years. The supplier which sold the machine had agreed to take back the machine for $4,000 at the end of the useful life. The company fiscal year-end is 31 December.

Compute the depreciation expense, accumulated depreciation and net book value of the machine for the years 2015, 2016, 2017 and 2018 using:

(i) The straight-line method.

(ii) The double-declining balance method.