Do you know anything about Pareto principle/analysis?
This is again a knowledge-based question. The Pareto principle states that 80% of the results come from 20% of the actions. This is a statistical analysis that is used by project managers to prioritize work. If you have enough experience as a project manager, most likely you have used this principle or at least a variation of it. Apart from explaining what it is, talk about how you used it in your previous job (if you did)