Do the multiple choice first, ! get them out of the way, spend at least a maximum of 5 minutes on each multiple choice. If you do not know the answer dont guess it or dont just stare at the question, but do all the other questions you know first.
Extension 1 students should be finishing the first 5 questions at least under the first 1 hour and a half. And then focus on the more difficult questions at the back of the paper.