BrainDen.com - Brain Teasers

witzar

Members

237

7

10. Black over White

Unfortunately not. I just wrote a recurrent equation (to count possible arrangements of marbles) and solved it using computer.

12. Penny's triple play

Can you prove, that required arrangement is not possible with odd number of coins?
13. Penny's triple play

Is it required for each coin to touch fully table surface with one of its faces?

21. Chess puzzle

When one has eliminated the impossible, then whatever remains, however improbable, must be the truth. This is what Sherlock Holmes used to say, who was a great master in retrograde chess. You can learn more about it from a great book with retrograde puzzles: The Chess Mysteries of Sherlock Holmes by Raymond M. Smullyan. Highly recommended. PS Well done, k-man
22. The Last Set

Well done, k-man.
23. The Last Set

The description of game Set in Wikipedia contains the following statement: If 26 Sets are drawn from a collection of 81 cards, the remaining 3 cards form a Set too. Can you provide a nice and smooth proof for it?