Level 3 is really short on quantitative problems in terms of diversity. This means that the same 20 or so calculation problems rear there heads routinely in both past morning sessions and mock exams. I noticed this earlier this year and made a thread about it.
Some Examples (By all means not exhaustive): Calculate Taylor Rule
Calculate Safety Margin (Fixed Income)
Calculated some part of Implementation Shortfall
Calculate Duration of Equity with Leverage
Turn Equity with X Beta into Synthetic Bullshit, or some variation of that
CPPI vs Constant Mix vs Buy and Hold
The bottom-line is that there is a very very very high probability that you will get asked how to do these few questions because such calculations are few in the Level 3 curriculum compared to Level 1 and 2. Make a list of these types of questions and practice doing them over and over again until they are second nature. These are the only free points that you will get in Level 3. Even Ethics is a crapshoot.
The rest of the test is a subjective nightmare where you will try to do your best with what you are given. Studying for these types of questions is pretty damn hard and I think practice writing essays and lucks play a role in them.