5. 9.25 The table that follows shows present worth values of the costs associated with using a presently owned machine (the defender) and a possible replacement (the challenger) for different numbers of years. Determine when the defender should be replaced using an interest rate of 10% per year and a 5-year study period. Show solutions using

(a) factors and

(b) a spreadsheet. Table Summary: A table divided into 2 main columns shows a replacement analysis for a 5-year period. The column headers are given as: Column 1, If in service this number of years; and Column 2, the PW in dollars per year is. Column 2 is further divided into two parts: Defender and Challenger. If in Service ThisNumber of Years The PW Value in $ Is: Defender Challenger 1 −36,000 −89,000 2 −75,000 −96,000 3 −125,000 −102,000 4 −166,000 −113,000 5 −217,000 −149,000 Defender Replacement Value