put 3 balls on each side,
* D( v& R+ q, l$ Z5 |+ |if balance, we can prove that all 6 balls on the 天平 is normal,
* X* a0 a% Q( vif not balance, we can prove that the 6 balls outside the 天平 is normal.) ^; G5 H7 _0 @0 ]# d9 Q% l
then use the proved-normal ball on one side and put the other ball on other side : z J3 W. }# y2 E t
to determine the abnormal is heavy and light |