- #1

Archinald

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**Hi**

1. Homework Statement

1. Homework Statement

On the party came n people. In the begining all of them have had exactly 3 friends among party members. During party some people made new friends and at the end of the party everyone had exactly 4 friends among party members. Set all numbers n for which the following statement is true. (if person A knows person B, then person B knows person A)

## Homework Equations

## The Attempt at a Solution

I found only some law that says -> "In any party of six people either at least three of them are (pairwise) mutual strangers or at least three of them are (pairwise) mutual acquaintances.", but I don't have an idea how to use that to solve this. Making combinations of possible cases i feel like it has to be n > 6 but i have no clue how to prove that.

Thanks in advance for all tips,

mfg