Your cat's summer kitty-cottage needs a new roof. You are considering the following two proposals and feel a 15-year analysis period is in line with your cat's remaining lives. (There is no salvage value for old roofs.)

(a) Construct a choice table for interest rates from 0% to 100%.
(b) Which roof should you choose if your MARR is 12%? What is the actual value of the IRR on the incremental cost?