Difference between revisions of "2021 IMO Problems/Problem 6"
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== Problem == | == Problem == | ||
| − | Let <math>m\ge 2</math> be an integer, <math>A</math> be a finite set of (not necessarily positive) integers, and <math>B_1,B_2,B_3, | + | Let <math>m \ge 2</math> be an integer, <math>A</math> be a finite set of (not necessarily positive) integers, and <math>B_1, B_2, B_3 , \ldots, B_m</math> be subsets of <math>A</math>. Assume that for each <math>k = 1, 2,...,m</math> the sum of the elements of <math>B_k</math> is <math>m^k</math>. Prove that <math>A</math> contains at least <math>m/2</math> elements. |
== Video solution == | == Video solution == | ||
| Line 6: | Line 6: | ||
== See also == | == See also == | ||
| + | {{IMO box|year=2021|num-b=5|after=Last Problem}} | ||
[[Category:Olympiad Combinatorics Problems]] | [[Category:Olympiad Combinatorics Problems]] | ||
Revision as of 10:38, 18 June 2023
Problem
Let 
be an integer, 
be a finite set of (not necessarily positive) integers, and 
be subsets of . Assume that for each 
the sum of the elements of 
is 
. Prove that contains at least 
elements.
Video solution
https://youtu.be/vUftJHRaNx8 [Video contains solutions to all day 2 problems]
See also
| 2021 IMO (Problems) • Resources | ||
| Preceded by Problem 5 |
1 • 2 • 3 • 4 • 5 • 6 | Followed by Last Problem |
| All IMO Problems and Solutions | ||
