So far, I have finished 35% of my overall Maths Methods mark. I got 19/20 for my PSMT which is worth 20%, (so 95%), however, I recently did my 15% exam, and can already tell I will barely pass it (I am expecting a 55% mark). Is that the end of the world for me? Say that I ace my other two exams (somehow), will that 55% mark forever hunt me down? Or will they bring up my mark?
If you get 55% on the exam you sat, you will be at ~27/35 so far - which is very good. You can think of it like this... Out of the 100 possible marks you can get, you have only lost 7 so far. So no, this will not hunt you down, you are on track to getting a very good end of year result
If you are worried about how you're tracking in methods, just remember that practice makes progress. Keep working at it and keep asking questions.
My biggest recommendation would be to sit practice papers - nothing beats 'em in my opinion
also, side question, how exactly is our overall mark calculated? Do we just add up all marks for the whole year and see how they add up out of 100?
Yep, your individual scores for each assessment will add up to some number out of 100. This is your
raw score and scaling is applied during the ATAR calculation process. You won't get to see what your result scales to but you will get access to a scaling report next year, and that will give you a rough idea of how your subject results scaled.
So, the PSMT in methods is worth 20% of your grade because it is only 20 out of the 100 points you can get in methods.