Yes, 750 would remain. (Assuming 50% of kids are boys, and averages actually working out, etc etc.) And yes, I would expect 1/3 of the remaining people to rai

Yes, 750 would remain. (Assuming 50% of kids are boys, and averages actually working out, etc etc.) And yes, I would expect 1/3 of the remaining people to raise their hands, so 250. The original problem does not go through this process, though. It didn't sort through a bunch of people to find some that match, and then start asking questions. It started with group, and some known information about them, and then started asking questions.