Hey, I think you would probably need 100 to top it personally. Most of the girls in my class last year got marks over 95, I'm not sure what the highest was but it would have been close. In extension, I got 49 in the assessment and 50 in the external and didnt get in the top list. A girl in my class got 50 and 50 and came fourth, so from that I reckon the top 4 in extension were ranked in order of whose actual HSC was the best. So for that reason I reckon latin continuers would be the same, a person may get 100 and top it, but if more do then it will be based on their raw HSC mark. This is just my opinion but, I have no idea if this is how it really works. Also remember, a mark of 100 in the HSC exam doesnt mean you didnt make a mistake, I know this because of the 50 i got in the extension- I can promise you, there is no way I had a perfect unseen!