put 3 balls on each side, tvb now,tvbnow,bttvb! K& ^% a) A) x, a' N. K3 W8 v1 R
if balance, we can prove that all 6 balls on the 天平 is normal, : e3 K* L! K2 M* M
if not balance, we can prove that the 6 balls outside the 天平 is normal.' m; z5 X3 t4 Q: K' L$ r: F
then use the proved-normal ball on one side and put the other ball on other side 6 L7 @3 x7 ~' Z/ Q. N9 p6 w# M
to determine the abnormal is heavy and light |