Net profit margin=PBIT/Sales But in BPP revision kit question number 27.1. Profit margin is calculated as PBT/Sales So it means that both of them acceptable? In the exam how we determine that which formula has to be used? Thansk in advance
It is normally PBIT (the net operating profit) / sales, and in a MCQ this is the formula you should use (unless, obviously, the question specifically says to do different).
For this question (a Section B type question) either would have been acceptable, provided you made the sensible comment on which ratio you had used.