MathDB
2014 Fall Team #3

Source:

March 26, 2022
combinatorics

Problem Statement

Suppose that in a group of 66 people, if AA is friends with BB, then BB is friends with AA. If each of the 66 people draws a graph of the friendships between the other 55 people, we get these 66 graphs, where edges represent friendships and points represent people. https://cdn.artofproblemsolving.com/attachments/5/5/7265067f585e3dfe77ba94ac6261b4462cd015.png If Sue drew the first graph, how many friends does she have?