You have ten coins, but two are fake, and weigh a little less. How many times do you have to use a two arm scale, in order to pick out the two fakes?

(In reply to Existential doubt by Federico Kereki)

I think most people will assume so otherwise the possibilities become much more numerous.  I would like to see the solution to this approach as well.  I will not even attempt it this way.  There could be Rx8,F-1,F-1 or Rx8,F-1,F-2 (the first way was solved in four, but you would need more weighings to determine which existed in the first place, and the second weighing seems to have many more possibilities than the four)  I would like to see both a computer and a logical (of course not saying computer solutions are not) solution to this one.

Posted by john on 2005-04-06 16:53:47