Hey guys.
Although its such a vague and naive way of calculating what you got, i have been attempting to predict my study score for both further maths and legal studies. And i hope that you will be able to

Knowing that the study score is out of fifty and the exam makes up 50% of that then we can say SACS make up the other 25 marks. So if you calculate your sac score as a decimal multiplied by 25 and add it to your predicted exam score as a decimal multiplied by 25 then its a very rough estimate.
For example, i got 98% for SAC results right, so that is equal to .98 * 25 thats 24.5/25 for the SACs +
I think i lost roughly 10 marks max on the exam so thats (50/60) multiply by 25. equals 21
Therefore without consideration of state average and school performance my study score would be 21 + 24 = 45.
Hope it helps. I KNOW ITS VAGUE BUT ITS THE BEST THERE IS