MathDB
Middle school logic problem in international mo

Source: IOM 2021 #4

December 10, 2021
algebralogic

Problem Statement

Six real numbers x1<x2<x3<x4<x5<x6x_1<x_2<x_3<x_4<x_5<x_6 are given. For each triplet of distinct numbers of those six Vitya calculated their sum. It turned out that the 2020 sums are pairwise distinct; denote those sums by s1<s2<s3<<s19<s20.s_1<s_2<s_3<\cdots<s_{19}<s_{20}. It is known that x2+x3+x4=s11x_2+x_3+x_4=s_{11}, x2+x3+x6=s15x_2+x_3+x_6=s_{15} and x1+x2+x6=smx_1+x_2+x_6=s_{m}. Find all possible values of mm.