put 3 balls on each side, " T2 A' U6 K/ `- O2 x: C, H
if balance, we can prove that all 6 balls on the 天平 is normal, tvb now,tvbnow,bttvb8 |2 G$ y0 B! Q2 b- y" r
if not balance, we can prove that the 6 balls outside the 天平 is normal.
& \% X+ v% t0 c5 `7 Ythen use the proved-normal ball on one side and put the other ball on other side
1 P& V5 z- S3 P$ K* `5 T4 |1 eto determine the abnormal is heavy and light |