Both assessments were open-book and non-zoom supervised.
The mid-semester test in this subject is tricky. It's not hard - you can easily answer all the questions (it's 20 MCQ), but the answers were very detailed and you really had to be on top of your game to get a good mark here. Answers would often have two phrases within them - for example, say the question was "What's 1+1?". One of the answer choices would be "1 + 1 is 2, but only if 2 is a negative number". Obviously the first part is correct, but the second phrase is false! Just imagine this in a finance context and you can see why this gets really tricky. This wasn't even the worst part - you always had "none of the above is true" or "more than one of the above is true" answer options to choose from. This meant even though one answer was obvious - you have to check for the others to see if it they were right. As such the average mark for this MST was 11/20, and it has been around this level historically. I don't think it gets better in level 3 subjects as I've heard haha.
The 80% exam is a bit scary, but honestly I found it a lot easier than the MST. It features 20 MCQ (similar to MST in terms of difficulty and style), around 8 true/false questions (where you had to explain why as well - this was the bulk of the exam as it was worth 40 marks), and 3 short/long answer questions (which were almost all mathematical based). New edit: this exam was scaled by 17 marks! Wow!
Chander only gave us one sample exam, which served us well. The questions were on par difficulty to the real exam, and the last question of both exams were similar. Still though, I couldn't get a sufficient answer here. You'll have to make sure you have a decent scanner/or use a tablet here, since Chander and the tutors only accepted handwritten answers. Make sure you upload early onto Gradescope!
In terms of the content tested, Chander mentioned 60% of the exam would be on weeks 6 onwards, and 40% in the first half. He definitely lived up to that, so be prepared to check closely on notes from weeks 1 - 5. As this exam was open book, you didn't need to remember much, but having organised notes will help you immensely and is the sole crediting factor to (potentially!) my exam success. I also recommend making "cheat sheets" - notes on how to tackle problems with formulae.