Hi there Kk,
It does depend heavily on the difficulty of your SACs, thus where you are ranked. However, I think 76% is about right.
A 35 would roughly place you in the top 26% of the state. As such, if you look at the grade distribution from last year (see below), a mid-high B+ on the exam (roughly 185/240 or 77%) would yield about a 35.
This is purely speculation, and is also reliant on SAC rankings, but if you try your best, I'm sure it will be fine.
https://www.vcaa.vic.edu.au/Documents/statistics/2023/section3/vce_biology_ga23.pdf
