# What is the longest amount of time it could take for them to all fall off?

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Ants on a stick may only move left or right. If they bump into each other they bounce off of each other and immediately move in the opposite direction maintaining speed the entire time. The only time they change speed is when they fall off of the edge of the stick.

If 25 ants are randomly put on a 1 meter long stick moving 1 meter per second, what is the longest amount of time it could take for them to all fall off?

posted Jun 23, 2015

## 1 Solution

+1 vote

Imagine that each ant is holding a flag and that when an ant bumps into another ant it gives its flag to the other ant. In this way, every ant always has a flag and a flag would never change direction. So each flag would head towards the edge at a rate of 1 meter per second and since the stick is 1 meter long, it would only take 1 second at most for each flag to fall off, and in turn, each ant.

solution Oct 7, 2015

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