ceteriz

divde the 12 balls into 3 sets of 4. . ]2 V6 F' C6 ~3 ]8 Y
weight any 2 sets.
7 E( y: `) n, w' D: nif the 2 sets are equal, then you know the heavy one is in the third
' w9 o# O5 {% N+ s, Htvb now,tvbnow,bttvbif one of the 2 is heavier, then the heavy one is in that setTVBNOW 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。4 k2 b) O' m7 m5 B( y, I; b
then divide the 4 balls into 2.公仔箱論壇1 ^0 M$ g, ]/ c3 n) G1 E" A" i" q: N
weigh them
1 {3 L3 _* O4 b公仔箱論壇and divide the heavier into 1
7 \# z0 U9 F8 K' t" V' s$ Band 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。9 `6 G9 p/ p; ?% K3 [
3 x weighing and get the ans.  % v8 z# a$ k, U+ L7 V( w. s
in less than 15 secs.