Solution by Spreadsheet
Follow the procedure for incremental ROR analysis. The spreadsheet in Figure 8–7 contains
the complete solution.
1. The alternatives are already ordered by increasing first costs.
2. These are cost alternatives, so there is no comparison to DN, since i * values cannot be
calculated.
3. Machine 2 is the first challenger to machine 1; the incremental cash flows for the 2-to-1
comparison are in column D.
4. The 2-to-1 comparison results in i * 14.57% by applying the IRR function.
5. This return exceeds MARR 13.5%, so machine 2 is the new defender (cell D17).
The comparison continues for 3-to-2 in column E, where the return is negative at i *
18.77%; machine 2 is retained as the defender. Finally the 4-to-2 comparison has an incremental
ROR of 13.60%, which is slightly larger than MARR 13.5%. The conclusion is to
purchase machine 4 because the extra investment is (marginally) justified.