Prove that the student was wrong during the counting.
Source: Kosovo IMO TST 2012 problem 1
April 22, 2012
modular arithmeticcombinatorics proposedcombinatorics
Problem Statement
A student had papers. He seleced some of these papers, then he cut each of them in pieces.He took these pieces and selected some of them, which he again cut in pieces each.The student took this procedure untill he got tired .After a time he counted the pieces and got pieces .Prove that the student was wrong during the counting.