put 3 balls on each side, " l! p6 I5 g* v; O
if balance, we can prove that all 6 balls on the 天平 is normal, 1 E+ N3 y; |) I
if not balance, we can prove that the 6 balls outside the 天平 is normal.5.39.217.774 i; e1 b# n* B
then use the proved-normal ball on one side and put the other ball on other side
( {( H6 E: F1 k# l& }) Z5.39.217.77to determine the abnormal is heavy and light |