ceteriz

divde the 12 balls into 3 sets of 4.
* i5 W6 O; k' G2 Etvb now,tvbnow,bttvbweight any 2 sets.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。  Z; W+ Y6 }! Y5 x3 g/ E
if the 2 sets are equal, then you know the heavy one is in the third
: i& B6 E: U" hos.tvboxnow.comif one of the 2 is heavier, then the heavy one is in that set! n, p# `0 D0 v& Z! D
then divide the 4 balls into 2.os.tvboxnow.com* s7 g' X; W* @+ \# H6 V( {
weigh them: O1 \) e. o& [3 v1 }
and divide the heavier into 1TVBNOW 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。/ p( P2 f$ W5 K3 K
and weight them.tvb now,tvbnow,bttvb) B! u$ e8 m& k9 g5 G2 f: ]
3 x weighing and get the ans.  6 w# K0 h- U+ q# X, N+ Z! w
in less than 15 secs.