41 letters on a circle, each letter is A or B
Source: Tournament of Towns, Senior Ο-Level Paper, Spring 2020 , p3
June 4, 2020
combinatorics
Problem Statement
There are letters on a circle, each letter is or . It is allowed to replace by and conversely, as well as to replace by and conversely. Is it necessarily true that it is possible to obtain a circle containing a single letter repeating these operations?Maxim Didin