I believe that thread278-163586 shows the solution, but does not account for the 10% ROI. If you look at the solution for PW = $50,000 + $50,000(P/F,i=10%,t=2) + $20,000(P/A,i=10%,t=4) - $10,000(P/A,i=10%,t=2). The last two parts of the equation that involve (P/A) are using the principle of...