first divide it into 3 groups... 4 for each group...公仔箱論壇/ M$ \7 l/ A' v$ K, q
den 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...
3 n$ G* g: |, ~5 _4 _2 ]den... left 4 balls...- |# F# n4 t0 d, X8 {3 |
when u use tat 3 groups to test... u oredi know it is heavier or not...0 d- R; x# l# N7 b! s9 {, B. r
so when testing these 4 balls... u juz nit 2 find out the heavier or lighter 1...
' i, M5 A$ ]/ O% U$ mtake the heavier or lighter 1... throw away tat 2 normal ball...3 ]/ o+ g# t( F1 p
den u juz nit 2 test the last 2 balls...$ c# ~: Y7 n0 s: t+ l5 C
same for now... take the heavier or lighter 1... |