MathDB
subsets of subset has same sum

Source: 2015 China TST 2 Day 2 Q2

March 19, 2015
combinatoricscombinatorics proposed

Problem Statement

Set SS to be a subset of size 6868 of {1,2,...,2015}\{1,2,...,2015\}. Prove that there exist 33 pairwise disjoint, non-empty subsets A,B,CA,B,C such that A=B=C|A|=|B|=|C| and aAa=bBb=cCc\sum_{a\in A}a=\sum_{b\in B}b=\sum_{c\in C}c