TST TAJIKISTAN Day 2 Problem 2
Source:
July 10, 2018
TSTAZE IzHO TST
Problem Statement
Problem 5. Consider the integer number n>2. Let a_1,a_2,…,a_n and b_1,b_2,…,b_n be two permutations of 0,1,2,…,n-1. Prove that there exist some i≠j such that:
n|a_i b_i-a_j b_j[color=#00f]Moved to HSO. ~ oVlad