>>Hi everyone,
>>
>>I wrote this puzzle in my reply to Renouir, but it was lost, since this thread became very big, so I'm starting a new thread for this simple puzzle.
>>
>>Ok, here it is:
>>
>>There are 10 wallets with 10 coins in each of them. In one wallet each coin is false, e.g. if true coin weights 1g. (sorry, I use metrics system :)), the false coin weights 0.9g. There is also precise scales. Attention, here is the question: how can you determine the wallet with all false coins in one operation? (You can weight only once).
>>
>> If this is too simple for you or you know the answer, please, let others think
>
>1-2-3-4-5-6-7-8-9-10

It was too simple... :)

Ok, your turn :)