put 3 balls on each side, 公仔箱論壇3 J u1 f" K/ u/ f# q$ r$ |0 E
if balance, we can prove that all 6 balls on the 天平 is normal,
( \: F# F. d; j% Xif not balance, we can prove that the 6 balls outside the 天平 is normal.
+ c; F# C, w& t. dthen use the proved-normal ball on one side and put the other ball on other side 公仔箱論壇+ m. P, h& D: d2 |- f* r
to determine the abnormal is heavy and light |