You have 12 coins. They are completely identical except six of them weigh 24g and the other six weigh 25g. You have only a balance scale to sort them out. What is the minimum number of weighings which guarantees all the coins to be sorted?
(In reply to
will this work by MIKE INCE)
No. There are a lot of possibilities that you are not considering. Remember, you have no idea which of the 12 coins is which. It is very possible that all 6 of your initial pairs will balance. Then what will you do? You then have 6 pairs, which you know are equal to each other, but you don't know which pairs are light and which are heavy. You have used 6 weighings, and essentially returned to the initial problem but with 6 unknown items (pairs of coins) instead of 12.
But don't give up -- it is a very interesting problem to think about....
re: will this work
