Welcome to MindCipher, a social repository of the world's greatest brain teasers, logic puzzles and mental challenges.


Likes 0

jleonard must be new here...

Ratings 0

No ratings yet!

Comments 2

The Easy Sum of 1..100?

Or you could use the formula n(n+1)/2. 100(101)/2 = 10100/2 = 5050

Cocktail Party

A fun way to solve this, since it's only 7 guests, is to construct a complete graph (k7). Then all you need to do is count up the edges.