Difference between revisions of "2024 USAMO Problems/Problem 2"

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Let <math>S_1, S_2, \ldots, S_{100}</math> be finite sets of integers whose intersection is not empty. For each non-empty <math>T \subseteq\left\{S_1, S_2, \ldots, S_{100}\right\}</math>, the size of the intersection of the sets in <math>T</math> is a multiple of the number of sets in <math>T</math>. What is the least possible number of elements that are in at least 50 sets?
 
Let <math>S_1, S_2, \ldots, S_{100}</math> be finite sets of integers whose intersection is not empty. For each non-empty <math>T \subseteq\left\{S_1, S_2, \ldots, S_{100}\right\}</math>, the size of the intersection of the sets in <math>T</math> is a multiple of the number of sets in <math>T</math>. What is the least possible number of elements that are in at least 50 sets?
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==Video Solution==
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https://youtu.be/eguz1OuckH0

Latest revision as of 09:09, 5 April 2024

Let $S_1, S_2, \ldots, S_{100}$ be finite sets of integers whose intersection is not empty. For each non-empty $T \subseteq\left\{S_1, S_2, \ldots, S_{100}\right\}$, the size of the intersection of the sets in $T$ is a multiple of the number of sets in $T$. What is the least possible number of elements that are in at least 50 sets?

Video Solution

https://youtu.be/eguz1OuckH0