I'm sort of having a panic attack right now because I really want a 50 in accounting as it's my only 3/4 in year 11.
I got 100% on the first sac but im really nervous for the second sac if I drop a mark.
Don't worry about the actual SAC marks throughout the year, what you want to make sure you're doing is: to improve on your answers and not make mistakes that you previously make. And, that you try to stay at the top of your cohort (top few ranks will do).
Most of your study score will come from your exam score, since this will moderate your sacs up/down as well as provide the majority of your study score percentage wise. I know that psych and accounting are different, but I dropped about 10-15 marks in sacs throughout the year for psych, and yet ended up with a 50. You definitely do not need to have 100% sacs throughout the year to get a 50

(unless you're in super competitive subjects, but accounting is not one of them
