Your raw marks get moderated to a 'Total Weighted Mark', (TWM) which factors in varying option questions or different prescribed texts. So, for example, it may factor in that for Chemistry, a 16/25 for Shipwrecks may be equivalent to a 19/25 in Industrial Chemistry (this is just an example). This puts all the subject's marks on an even playing field. This TWM is aligned, based on the total number of marks received by students for that exam that year (so a 70/100 may align to a 90, based on how hard the exam was). This aligned mark becomes the 'Exam Mark'. Your rank has no effect on your Exam Mark.