Archive for May, 2007

Ants

Friday, May 11th, 2007

This is probably the best riddle I know of.

There are 1000 ants walking on a horizontal stick, 1m long.

Each ant is walking at a constant rate of 1m/hour.

The ants start out in random locations on the stick, some walking to the left and some to the right.

Whenever two ants meet they reverse their direction, as follows:

Riddle Illustration

Whenever an ant reaches one of the ends of the stick, it falls off (eventually all ants will fall).

What is the longest time it will take the last ant to fall off the stick?

The Ants riddle is one of the best riddles ever. It requires an imaginative mind, but does not require any knowledge of mathematics. A talented 6 year old can solve it!That is not to say it is very easy, but you can solve it yourself. DO NOT DESPAIR!

If you already solved the riddle and want to see the solution – visit the second page below.