MathDB
2n cards

Source: Baltic Way 2001

November 17, 2010
algebra unsolvedalgebra

Problem Statement

There are 2n2n cards. On each card some real number xx, (1x2n)(1\le x\le 2n), is written (there can be different numbers on different cards). Prove that the cards can be divided into two heaps with sums s1s_1 and s2s_2 so that nn+1s1s21\frac{n}{n+1}\le\frac{s_1}{s_2}\le 1.