gensy850711

first divide it into 3 groups... 4 for each group...
) l8 V; ?( g: f6 m! J- v5.39.217.77:8898den use 2 groups to test... if the weight is same... den throw away these 2 groups.. if not... use another 1 group to test with tat 2 groups... throw away the same weight groups...! Y% _3 Q+ q2 j) |+ A- G( ]
den... left 4 balls...
) f8 S; |: N; X  \7 s* A, r5.39.217.77:8898when u use tat 3 groups to test... u oredi know it is heavier or not...
6 _" T8 v' ~7 C% K+ F5.39.217.77:8898so when testing these 4 balls... u juz nit 2 find out the heavier or lighter 1...
! A& a5 E# e5 c' q( ytake the heavier or lighter 1... throw away tat 2 normal ball...公仔箱論壇: N: `5 R, H. n
den u juz nit 2 test the last 2 balls...tvb now,tvbnow,bttvb: Q& i3 k5 Y; V
same for now... take the heavier or lighter 1...