1979 USAMO Problems/Problem 5: Difference between revisions

Revision as of 22:44, 11 April 2012

Let $A_1,A_2,...,A_{n+1}$ be distinct subsets of $[n]$ with $|A_1|=|A_2|=\cdots =|A_n|=3$ . Prove that $|A_i\cap A_j|=1$ for some pair $\{i,j\}$ .

This problem needs a solution. If you have a solution for it, please help us out by adding it.

@@ Line 4: / Line 4: @@
 ==Solution==
+{{solution}}
+==See also==
 {{USAMO box|year=1979|num-b=4|after=Last Problem}}

1979 USAMO (Problems • Resources)
Preceded by Problem 4	Followed by Last Problem
1 • 2 • 3 • 4 • 5
All USAMO Problems and Solutions