2001 IMO Shortlist Problems/C8
Problem
Twenty-one girls and twenty-one boys took part in a mathematical competition. It turned out that each contestant solved at most six problems, and for each pair of a girl and a boy, there was at least one problem that was solved by both the girl and the boy. Show that there is a problem that was solved by at least three girls and at least three boys.
Solution
This problem needs a solution. If you have a solution for it, please help us out by adding it.