MathDB
8 heaps of 251 coins each, 251 heaps of 8 coins each, regular 2008-gon

Source: Indian Postal Coaching 2009 set 4 p4

May 26, 2020
combinatorics

Problem Statement

At each vertex of a regular 20082008-gon is placed a coin. We choose two coins and move each of them to an adjacent vertex, one in the clock-wise direction and the other in the anticlock-wise direction. Determine whether or not it is possible, by making several such pairs of moves, to move all the coins into (a) 88 heaps of 251251 coins each, (b) 251251 heaps of 88 coins each.