Engineering Economy 7th Edition by Leland Blank ,Anthony Tarquin

Exercise 39

If a revenue alternative has a negative AW value and it was correctly calculated, it means the following:
a) The equivalent annual worth of revenues does not exceed that of the costs.
b) The estimates are wrong somewhere.
c) A minus or plus sign of a cash flow was entered incorrectly into the PMT spreadsheet function.
d) The alternative should have a longer life so revenues will exceed costs.