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6

Part of 2007 Bosnia Herzegovina Team Selection Test

Problems(1)

Ann chooses subsets

Source: Bosnia and Herzegovina TST 2007 day 2 problem 3

5/13/2014
The set AA has exactly n>4n>4 elements. Ann chooses n+1n+1 distinct subsets of AA, such that every subset has exactly 33 elements. Prove that there exist two subsets chosen by Ann which have exactly one common element.
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