Israel 2011 Q6 - Red and blue numbered cards
Source: Israel National Olympiad 2011 Q6
August 8, 2019
combinatoricscards
Problem Statement
There are red cards and blue cards. Each card has a positive integer between and (inclusive) written on it. Prove that we can choose a (non-empty) subset of the red cards and a (non-empty) subset of the blue cards, so that the sum of the numbers on the chosen red cards equals the sum of the numbers on the chosen blue cards.