Quote Originally Posted by Expert View Post
There are 12 stones, 11 of equal weight, 1 of unequal weight (either heavier or lighter).

Use 3 weighings on a balance scale to tell what stone has a different weight and if it is heavier or lighter.

Can anyone solve this?
Make 4 sets of 3 each. A,B,C,D
compare A & B. If they are equal, take one of each stone out from C and D.

now compare C & D. If they are equal... Add the 2 stone that you took out back... you will know which one is odd and you will if it was heavy or light.

IF A&B were not equal... take one stone each out from A&B.. if they the weight level, you know which one is odd and also know heavy or light ( by looking at wheather the light side went down or heavy side went up).

If they still don't level... take one stone each out again from A&B.