This problem follows on from 9 Weights
You have twelve weights, one of which is heavier or lighter than the rest, but you don't know which one is heavier or lighter. Using just 3 weighings on the balance, can you identify which weight is the odd one out, and whether it is heavier or lighter?
Full Screen Version
If you can see this message Flash may not be working in your browser
Please see http://nrich.maths.org/techhelp/#flash to enable it.