Practice enough to understand the interface and solve representative problems consistently; there isn't one universal number of hours for Solve or Casey.

Your starting skill level, the specific assessment version and how much time you have matter more than a fixed practice quota. Repeating the same mock without reviewing mistakes has diminishing returns.

A student comfortable with quantitative reasoning may need more practice interpreting unusual instructions, while someone new to timed business problems may need focused drills first.

Confirm the assessment in your invitation, run a diagnostic, and use timed practice to target weaknesses. Plan your sessions around coursework, choosing the relevant resources for McKinsey Solve practice or BCG Casey preparation rather than trying to complete every practice exercise.

For me the hard bit was pacing. I knew the math but rushed the last part of practice.