Suppose a business purchases a new tractor at an original cost of $42,000. Further, suppose this tractor has a useful life of 8 years and a salvage value of $10,000.

a) Use the Straight-Line Method to find the yearly depreciation on this tractor.

b) How much is this tractor worth after 3 years?

c) Find a formula that calculates the tractors worth after t years. What is the maximum allowable value for t?