IMO Shortlist 2012 problem C3
Dodao/la: arhiva3. studenoga 2013.
square table some cells are white and the remaining ones are red. Let
be the number of triples
of cells, the first two in the same row and the last two in the same column, with
red. Find the maximum value
Izvor: Međunarodna matematička olimpijada, shortlist 2012