We open with a simple mathematical puzzle that is easily solved using only elementary reasoning. Imagine a party where some guests are friends while others are unacquainted. Then the following is always true:

*No matter how many guests there are at the party, there are
always two guests with the same number of friends present.*

If you wish, try proving this before reading on. The proof is outlined at the end of this post.

You must be logged in to post a comment.