If we attempt a question with 5 marks and there is 1-2 marks for each calculation and we do one part wrong which will indirectly effect the next part would we be rewarded for correct working of the next part or not?
Yes you would be given the marks if you had shown the correct workings based on your figures. The same applies if you are asked to discuss the results of previous calculations – if the discussion was correct for your (wrong) figures then you would still get full marks for the discussion.
You do not lose marks twice for the same mistake 🙂