16.7 Jobe Concrete Products placed a new sand sifter into production 3 years ago. It had an installed cost of $100,000, a life of 5 years, and an anticipated salvage

of $20,000. Book depreciation charges for the 3 years are $40,000, $24,000, and $14,000, respectively. (a) Determine the book value after 2 years. (b) If the sifter's market value today is$20,000, determine the difference between its cur-rent book value and its market value. (c) Deter-mine the total percentage of the unadjusted basis written off through year 3.