### finding odd one out of 12 balls in 3 weighings

The problem is you have 12 identical balls (of any kind), one ball either
lighter or heavier than the other 11. A scale is provided to you but only
three weighs are allowed. How can you possibly figure out which is the odd ball?

1. we can do this in 3 steps with a balance by dividing into 3 groups of 4 balls each or 2 groups of 6 balls each or ...

but with a weighing scale, can we do it with 3 weighs only? I need 4.

2. no you can do it in 3 weighings...try in a group of 3 balls....

3. i m still not able to figure out any way...please explain.

4. @jainendra i can send you an flow diagram using that you can find out .every ball has equal probability of being heavier or lighter.

5. To give an Explanation: You have 12 balls divide equally.
For the 6 balls again divide to put three balls in each pan if they are equal. Take 6 balls and repeat. if not, Take 3 balls which weight heavier. Among those 3 balls Take two balls and weigh them. If they are equal, third ball is heavier n odd otherwise the ball which is weigh heavier is the odd one.

6. @Anand in the problem it is said that ball may be heavier or lighter than other so rethink over it.The main problem is if in the first weighing the 3 balls are not equal...please do give your suggestions...

7. use hybrid set after 1st weighing