some marbles are distributed over 2n + 1 bags, each no of marbles the same
Source: 1990 ITAMO p6
January 31, 2020
combinatorics
Problem Statement
Some marbles are distributed over bags. Suppose that, whichever bag is removed, it is possible to divide the remaining bags into two groups of bags such that the number of marbles in each group is the same. Prove that all the bags contain the same number of marbles.