MathDB

Given is a set of

2n

cards numbered

1,2, \cdots, n

, each number appears twice. The cards are put on a table with the face down. A set of cards is called good if no card appears twice. Baron Munchausen claims that he can specify

80

sets of

n

cards, of which at least one is sure to be good. What is the maximal

n

for which the Baron's words could be true?

Problem Statement