Bouncy Ants...
One hundred ants are dropped on a 1 meter long stick. Each ant is traveling either to the left or the right with constant speed 1 meter per minute. When two ants meet, they bounce off each other and reverse direction. When an ant reaches an end of the stick, it falls off.
Over all possible starting configurations of the ants, what is the longest amount of time (in SECONDS) that you would need to wait to guarantee that the stick has no more ants ?
The problem is not original.
The answer is 60.
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1 solution
Two ants bouncing off each other is exactly the same as two ants that pass through each other, in the sense that the positions of ants in each case are identical.
So the motion of all ants can be viewed as being independent. Thus all ants will fall off after crossing the length of the stick, that`s 1 meter. The longest you need to wait is 60 seconds...