You 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' remaining lives. (There is no salvage value for old roofs.)
Thatch slate
First cost $20 $40
Annual upkeep 5 2
Service life, in year 3 5
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?