MathDB
Smallest possible value of m

Source: Dutch Mathematical Olympiad

September 19, 2005

Problem Statement

Let a1,a2,a3,a4,a5a_1,a_2,a_3,a_4,a_5 be distinct real numbers. Consider all sums of the form ai+aja_i + a_j where i,j{1,2,3,4,5}i,j \in \{1,2,3,4,5\} and iji \neq j. Let mm be the number of distinct numbers among these sums. What is the smallest possible value of mm?