(I'm creating a new post as I am no longer offering Physics and Chemistry tutoring, however, my old post along with testimonials/recommendations can be viewed here...
I'd recommend doing something practical if you do the TSP showcase in first semester - personally I did a practical physics project which I found enjoyable. You'll have the option of doing a maths project but it'll most likely just require you to (essentially) read a textbook and learn about an...
Yeah, a lot more than 10 students get 100 for 3U every year. If more than 10 students get 100 internal mark and 100% raw exam mark, the Board of Studies uses other means to pick which papers are the top 10 in the state (for example, they look at the conciseness of your answers).
Interesting that they chucked a combinatorics problem in Q16 when they did that last year (to be fair, the problems were quite different though).
From a quick glance it seems like the paper only started to get interesting at around q15