ceteriz

divde the 12 balls into 3 sets of 4. ) S! c% B/ V" A7 m+ w
weight any 2 sets.
3 S) x8 j. \3 R# W2 P) Qif the 2 sets are equal, then you know the heavy one is in the third
7 [4 _. ?' D! M# a+ F$ T* I. }- jTVBNOW 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 one of the 2 is heavier, then the heavy one is in that set. @3 c! X8 b3 G- n
then divide the 4 balls into 2.公仔箱論壇% [3 ]( u! y0 ^. g3 t, |5 |
weigh them, m# T4 T6 N- R. i
and divide the heavier into 16 S9 l& z- l2 p; {+ L: z6 m
and weight them.TVBNOW 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。# e, n  G4 G1 S- j/ d7 T
3 x weighing and get the ans.  # Q6 ^/ c% X0 ]" H+ @  u
in less than 15 secs.