There are two main factors that will determine whether a mark in the band E3 range in Mathematics Extension 2 will be possible. The first one is cohort strength. Being ranked last in a subject is not good. However, the extent to which this applies differs between higher-ranked schools and lower-ranked schools. Being ranked last in a subject at a lower-ranked school can be interpreted as being in a much worse position than being ranked last in that subject at a higher-ranked school. In your case, the high academic capability of your cohort, which can reasonably be assumed given your school rank, may provide some hope. However, this will heavily depend on your cohort's performance in the Mathematics Extension 2 HSC exam (including the student who achieves the lowest HSC exam mark, which can also be you) as was mentioned in the above posts. This is a factor that you can no longer control at this stage.
The second factor is your own performance in your Mathematics Extension 2 HSC exam. This is where you have the most control. By doing your utmost in preparation for the HSC exam, you will become more likely to perform favourably, resulting in a favourable HSC exam mark and consequently increasing your chances of achieving an overall HSC mark in the band E3 range.
Overall, with thorough and effective preparations, as well as a bit of luck, you will hopefully be able to achieve a mark in this range.
I hope this helps!
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