TNOCF

Q85 on the Schweser book 2 exam 1 afternoon session asks to calculate the final period after-tax cash flows. The answer is to add the CF from the final period plus the TNOCF. I got the question wrong because I only calculated the TNOCF for the replacement project. Is there a way to differentiate when to add both final year CF and TNOCF or just calc TNOCF? The Schweser text book examples all just ask to calc one or the other, separately, not together.