A company purchased a machine for $75,000 that was expected to last 6 years and have no salvage value. At the beginning of the machine's fourth (4th) year the company spent $20,000 in betterments that increased the machine's production capacity. Straight-line depreciation was used throughout the machine's 6 years of useful life. Calculate the depreciation expense for the fourth full year of the machine's useful life. (10 pts) (Note: The cost of the betterment increases the book value before recalculating the new depreciation.) Show all work!