MathDB

7501

points in a

96 \times 96

square is marked. We call the

4 \times 4

square without its central

2 \times 2

square a frame. Prove that there exist a frame with sides parallel to the

96 \times 96

square (not necessarily from the grid lines) that contains at least

10

marked points.
Proposed by Negar Babashah, Shima Amirbeygie Rated 5

7