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divde the 12 balls into 3 sets of 4.
2 C' M8 [0 G9 @+ Mtvb now,tvbnow,bttvbweight any 2 sets.
: ]; e' x: f, `7 R" f2 a1 u3 r7 bTVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。if the 2 sets are equal, then you know the heavy one is in the third公仔箱論壇" K/ V) ^, n* S' p$ n" @
if one of the 2 is heavier, then the heavy one is in that set/ O, m& ^8 X+ Y( E2 K
then divide the 4 balls into 2.
" t8 j8 t5 q( |; b! a! S3 A5.39.217.76weigh them
$ |4 `9 D  p) j$ n0 zand divide the heavier into 1公仔箱論壇7 `, D& \  u" X1 e7 K
and weight them.公仔箱論壇1 ]$ X. S7 h* g  e' _3 Q& j, O
3 x weighing and get the ans.  
' D& Y& a4 @) c8 }1 J+ i5.39.217.76in less than 15 secs.