Problem

The Enemies of My Friends are My Enemies

Author: munch

In a group of N people, each pair of people are either friends or enemies. The rule “the enemies of my friends are enemies” holds for every person. If each person has 20 enemies, find the sum of the values of N.


Show/Hide Problem Tags

Problem Tags: Counting and probability Graph theory

Want to contribute problems and receive full credit? Click here to add your problem!
Please report any issues to us in our Discord server