Personally, I never used to waste time, I would just hit my best of 5 in section B then do what I can in sectionA . If I don't know I skip. I used like 1hr doing the paper and the other hour helping my friends.
The habit went all the way up to campus.
High School was crazy, mtu unakalia maths exams for 2 hours 30 minutes lakini unatoka na yako sigistin.