Answer:
See below and images.
Step-by-step explanation:
For part 1 refer to the images attached of each depreciation method.
The double declining method uses the rate of straight line method and doubles it. Rate = 1 / Useful life
For part 2)
As the company wants maximum revenue recording in early years, it shall use the straight line depreciation method as in the first years, this yields the least depreciation when compared to other methods. Year 1 depreciation for each method are as follows,
Straight line = 19,800
Double declining = 43,600
Units of mileage method = 20,800
So the method that meets company's objectives is the straight-line method.