6. (13 points) An engineering company buys state-of-the-art computers for it's employees at a cost of $5000/computer. Using "Sum-of-Digits (SOYD)" method compute (i) the cumulative depreciation at the end of year 3 and (ii) the book value at the end of year 4. 7. (13 points) The particulars of pump A and B are listed in the table below. Which pump should be bought given an effective annual interest rate of 9%. Description Initial Cost ($) End-of-Uueful-life salvage value (S) Estimated Annual Benefits ($) Pump A 5000 1000 6 Pump B 8000 2000 9