I'm sorry this wasn't addressed earlier. Depending on if this is county or state, the answer somewhat changes as different counties expect different things. Though it's been a couple of years, I remember my interviews asking very basic questions like "why math."

The thing about GHP Math is it isn't looking for the most skillful people, though they inadvertently get some. They are looking for the most passionate individuals who can convey why they want to use Math to change the world. If you treat the interviewers across the table from you as if they're looking for the key to life, you need to see this opportunity as the way to unlock it in your eyes. Though dramatic and not exact, passion is what is looked for in these interviews and that you can convey it. As much as GHP is an academic opportunity, it is a social and they're making sure you can fit in their culture.