I NEED THIS TONIGHT!!! 8-9-05!!!!!!!

weigh 2 groups of 6 pills.

Split the heaviest group into 2 groups of three but weigh only one group. Since you know the weight of the group of six, you can tell from the weight of the group you weigh if it is divisible by 3 (since they all weigh the same) or if not divisible by three you know it contains the heavier pill.

Using the heaviest of the group of three, weigh two. If divisible by two, take the one in your hand. If not divisible by two, take both of the pills on the scale.

Umm, my bad, but you can only take one pill... sorry for leaving that part out, and you don't know wether it is lighter or heavier...



Thanks to whoever can help!

Re: I NEED THIS TONIGHT!!! 8-9-05!!!!!!!


Your questions makes absolutely no sense. You say that "each pill looks, and weighs the same, except one has a different weight. How can they all weigh the same and still have one of a different weight?

Notice the word, "except"... Each pill looks, and weighs the same, except one has a different weight.




Keep trying, I'm workin on it too!

Notice the word, "except"... Each pill looks, and weighs the same, except one has a different weight.




Keep trying, I'm workin on it too!

Oh, that makes all the difference. In that case. Number the pills 1 through 12. Weigh pills 1,2,3,4 against pills 5,6,7,8. If they balance, weigh pills 9 and 10 against pills 11 and 8. If they balance, we know pill 12, the only unweighed one is the needed pill. The third weighing indicates whether it is heavy or light.

If, however, at the second weighing, pills 11 and 8 are heavier than pills 9 and 10, either 11 is heavy or 9 is light or 10 is light. Weight 9 with 10. If they balance, 11 is heavy. If they don't balance, either 9 or 10 is light.

Now assume that at first weighing the side with pills 5,6,7,8 is heavier than the side with pills 1,2,3,4. This means that either 1,2,3,4 is light or 5,6,7,8 is heavy. Weigh 1,2, and 5 against 3,6, and 9. If they balance, it means that either 7 or 8 is heavy or 4 is light. By weighing 7 and 8 we obtain the answer, because if they balance, then 4 has to be light. If 7 and 8 do not balance, then the heavier pill is the needed pill.

If when we weigh 1,2, and 5 against 3,6 and 9, the right side is heavier, then either 6 is heavy or 1 is light or 2 is light. By weighing 1 against 2 the solution is obtained.

If however, when we weigh 1,2, and 5 against 3, 6 and 9, the right side is lighter, then either 3 is light or 5 is heavy. By weighing 3 against a good pill the solution is easily arrived at.

I'm dead.(When this happens to me I take all the pills)

Three groups of four, weigh two groups, thus finding which group is the heaviest, take that group and weigh two against two, again one group will be heavier, one against one to find the heaviest. ----- three weighings.

Intrreped, your a life saver. Thanks.