hello1997

分3組4隻波子秤8 D* K( u  E7 n# m+ h

& b% {3 k0 I# j0 tGroup A: 1,2,3,4
1 `% A& K2 h6 B2 c4 KGroup B: 5,6,7,8) g" V8 u7 j. `
Group C: 9,10,11,12
5 X, ?2 d; h( M! m2 dGroup D: 13. S1 P' Z4 u4 E7 o: W  e; F. _  `0 P

& k; Z- r4 ?; m% cRound 1
2 \/ g; x! P% [Group A vs Group B# m! K7 N. b5 g
如A and B一樣, 即較輕一粒在Group C or D
2 S4 ]+ ~1 p% R3 B# P+ q2 I1 @2 I& i0 g
Round 2, I! |# h( a- \9 c6 w/ ~
再在Group C拆成:6 ], Q% C3 Q5 B0 a5 G& I
Group Ca: 9,102 x' f& }* P0 L! {/ Y! R
Group Cb: 11,12
& q8 M2 L' M/ \然後再秤, 如一樣, 即13為較輕一粒." `5 |! @% ~; b! X6 @) \3 M
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如不同, 即較輕一組有一粒較輕波子在其中,
8 I2 }5 K- s$ e3 v2 P要再秤, Round 3, 之後便知答案.
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9 n; E: L, F  o* Ke.g. #1 假設10為較輕的一粒" w/ m0 Z4 r! C% b
Round 1) t/ f0 i$ c% `0 N7 y. m, y
1,2,3,4 vs 5,6,7,8 = equal2 k# ~# h1 k' [  \0 p. d

' [% S3 _2 {/ e5 G2 I  _* ^( m; sRound 26 ^) R7 n3 Q& s1 S! m6 ]1 }
9,10 vs 11,12 = 9,10 < 11,12# O- T# v2 |* x- ]# Z, V

4 m2 w$ {- L5 fRound 31 R7 \- j. p* [
9 vs 10 = 9 > 10
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/ R' e+ {5 w& w7 B9 ^) u" r$ w9 |The answer is 10.
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e.g. #2 假設7為較輕的一粒( W* ~) y7 K8 f# Z) T+ U- b2 q
Round 1
. [4 @4 ]  z0 p& Q0 g1,2,3,4 vs 5,6,7,8 = 1,2,3,4 > 5,6,7,8
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Round 2* O, p+ F( _! [$ i
5,6 vs 7,8 = 5,6 > 7,87 v4 v. n, K0 ?# E/ e4 R* n" t- {# A

$ j" ]$ D( _6 _6 s4 FRound 32 W3 E5 {% H5 D' T5 \' W# Z; |
7 vs 8 = 7 < 8
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The answer is 7.& M6 q( k: }3 r6 r, g* \

/ M: |2 E1 y8 m9 Ne.g. #3 假設13為較輕的一粒  b9 q) A) m% Z  L4 `
Round 1
# G2 ]2 t0 V+ L' q9 i. Z1,2,3,4 vs 5,6,7,8 = equal
5 Q- Q+ H9 v4 i- Z, N- @. `6 q8 ]- I7 X+ b& a
Round 26 A5 `2 I- ]$ H" I! e, N* N/ p
9,10 vs 11,12 = equal
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No Round 3
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& {1 T3 W" Y9 R9 l1 r- hThe answer is 13.
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. T* S- O$ t% K; V$ M- F唔知我答得正唔正確呢?! 6 r7 x  n4 }( Z/ T- q+ b9 K

- R* y2 h# k$ T3 s[ Last edited by hello1997 on 2007-3-2 at 12:39 AM ]