January 1, 2018, a machine was purchased for $90,000. The machine has an estimated salvage value of $6,000 and an estimated useful life of 5 years. The machine can operate for 100,000 hours before it needs to be replaced. The company closed its books on December 31 and operates the machine as follows: 2018, 20,000 hours; 2019, 25,000 hours; 2020, 15,000 hours; 2021, 30,000 hours; and 2022, 10,000 hours. Instructions a. Compute the annual depreciation charges over the machine's life assuming a December 31 year-end for each of the following depreciation methods. 1. Straight-line method. 2. Activity method. 3. Sum-of-the-years'-digits method. 4. Double-declining-balance method. b. Assume a fiscal year-end of September 30 . Compute the annual depreciation charges over the asset's life applying each of the following methods. 1. Straight-line method. 2. Sum-of-the-years'-digits method. 3. Double-declining-balance method