put 3 balls on each side,
7 |4 @* S' Z* R$ B公仔箱論壇if balance, we can prove that all 6 balls on the 天平 is normal, $ l9 O/ q Z0 F) \
if not balance, we can prove that the 6 balls outside the 天平 is normal.
+ S0 r8 z3 Y+ z& |then use the proved-normal ball on one side and put the other ball on other side 1 a, J; G- N5 {9 k$ Z! s+ V
to determine the abnormal is heavy and light |