Prior Koal Company, Inc. purchased a new mining machine at total cost of $1,440,000 on August 1 of the current year. The firm estimates that machine has useful life of 6 years or 9,200,000 tons of coal and 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 machine assuming that company uses straight-line method.

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

Year Tons of coal

1 680000

2 1420000

3 1590000

4 990000

5 700000

6 3820000

Total

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