Prior Koal Company, Inc. purchased a new mining machine at a total cost of $1,440,000 on August 1 of the current year. The firm estimates that the machine has a useful life of 6 years or 9,200,000 tons of coal and a residual value of $60,000 at the end of its useful life. The following schedule indicates the actual number of tons of coal mined with the machine per year:

a. Prepare the depreciation schedule for the machine assuming that the company uses the straight-line method.

b. Prepare the depreciation schedule for the machine assuming that the company uses the units of activity method.

b. Prepare the depreciation schedule for the machine assuming that the company uses the double-declining balance method.