Divide the 12 balls into 4 groups of 3's. ( f9 `/ n7 G% y+ g; O: E: a5 `/ OWeigh group 1 & 2 `, f: J* o* o! H0 A
then weigh group 2 & 3 ; r( m* H+ r0 I/ W5.39.217.77If the results are Equal & Equal, it means the ball with the different weight is in group 4. 8 w' d8 j ?8 f公仔箱論壇If the results are Equal & Unequal, it means the ball is in group 3.3 E, Z+ A4 |$ z) ?3 e
If the results are Unequal & Equal, it means the ball is in group 1. J* `6 M" }, h9 y# `6 V# R2 |6 ~
If the results are Unequal & Unequal, it means the ball is in group 2.4 C Y; \' q/ i
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Once you determine the group that contains the ball. . i) c( M9 J' l* T8 H. qSimply weigh two of the balls