Equipment was acquired on June 1, 2015 for $28,000. The equipment has a salvage value of $3,000 and a useful life of 10 years. What was depreciation for 2015? (Round to the nearest dollar) use straight line method and

Equipment was acquired on January 1, 2015 for $65,000. The equipment was depreciated using the straight-line method and had a salvage value of $3,000 and a useful life of 10 years. At the at end of 2020 (before recording the adjustment for 2020), management revised the total useful life to 15 years and a salvage value of $4,000. What is the revised annual depreciation? using revised depreciation

can i get explanation how to use and count the useful time?