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Urning more balls
Posted 25 May 2014 - 07:06 AM
An urn contains a certain number of black balls and a certain number of white balls.
You draw two balls from the urn at random.
If they are of opposite color you throw them away and put a white ball into the urn.
If they are of the same color you throw them away and put a black ball into the urn.
You reduce the number of balls by 1 each time.
After some number of repetitions there will be only a single ball left in the urn.
If you are told the respective numbers of black and white balls at the outset,
can you accurately predict the color of that final ball?
- Bertrand Russell
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