put 3 balls on each side,
8 N2 F' n+ d! j, s# hif balance, we can prove that all 6 balls on the 天平 is normal, ( o$ \, f, ?+ I# j7 V
if not balance, we can prove that the 6 balls outside the 天平 is normal.5.39.217.77:88985 w; e' H& ` H5 I+ z* i5 Z
then use the proved-normal ball on one side and put the other ball on other side
4 K5 c5 g8 f! |% R7 {( \ E公仔箱論壇to determine the abnormal is heavy and light |