MathDB
There is a 100 × 100 square table

Source: Belarus IMO TST 1995 Day1 P1

November 28, 2015
combinatorics

Problem Statement

There is a 100 x100 square table, a real number being written in each cell.AA and BB play the following game. They choose, turn by turn, some row of the table (if it has not been chosen before). When AA and BB have 5050 rows chosen each, they sum the numbers in the corresponding cells of the chosen rows, and then sum the squares of all 100100 obtained numbers and compare the results. AA player who has the greater result wins. Player AA begins. Show that AA can avoid a defeat.