Yes, it is possible and as Ragerunner has said, you can get a high UAI with any combination of subjects, not just subjects which are assumed to have 'good' scaling. It's all up to you!
Having said that, you can get 50.00 UAI if you did those subjects and performed extremely bad (this isn't meant to scare you, I'm just saying that the subject isn't the real issue here, it's the student).
Good luck with your subjects, I hope all goes well for you
thats a silly question, you can get 98+ with any combination. im doing (did) an extra extension on english and math, as well as chem and phys, did them all reasonably well, and im not sure whether i'll get 98+ or not