On January 1, 2018, Zak Company purchases equipment for $24,000, with an estimated useful life of 4 years and no salvage value. The straight-line depreciation method is applied and financial statements are prepared yearly. On January 1, 2020, the company reassesses the condition of the truck and finds that it can extend its useful life by 2 more years. What is the amount of the revised annual depreciation? *