Williams company purchased a machine on January 1, 2014 by paying cash of $300,000. The machine has an estimated useful life of six years is expected to produce 400,000 units and has an estimated residual value of $40,000.

a. Calculate depreciation expense to the nearest whole dollar for each year of the machine's useful life under

1. straight-line depreciation method

2. double declining - balance method

b. What is the book value of the machine after three years using the double declining balance method?

c. What is the book value of the machinery after three years using the straight-line method?

d. If the machine was used to produce and sell 120,000 units in 2014 what would be the depreciation expense using the units of production method?