hello1997

分3組4隻波子秤8 @+ S% C0 d, Y& G% `
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Group A: 1,2,3,42 I/ }7 V& ^  A* i3 j: b3 G6 l
Group B: 5,6,7,8# w" ]. `- n" v" I6 q7 }
Group C: 9,10,11,12
$ S0 C4 p& o1 U9 [  yGroup D: 13
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Round 1' u/ l7 L$ R% L  l
Group A vs Group B% Y2 i, x. _, d4 w/ a
如A and B一樣, 即較輕一粒在Group C or D
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+ P) w, k$ H( XRound 2# q1 D/ X% E1 o6 e
再在Group C拆成:8 R! U' i% h' f( ~/ K  p
Group Ca: 9,10& ^. O5 r2 x+ o, z$ O1 O! K
Group Cb: 11,12
* v: t0 L( v$ Q3 ^; |然後再秤, 如一樣, 即13為較輕一粒.
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如不同, 即較輕一組有一粒較輕波子在其中,
0 |/ v) h! p+ L' t要再秤, Round 3, 之後便知答案.+ k$ `& s+ C; a

% A: ]% p5 N- f, [' oe.g. #1 假設10為較輕的一粒+ D, ^6 x7 X" T' d( ]6 K4 F/ E
Round 1
3 N! I- _+ ?6 o% q" a1 m1,2,3,4 vs 5,6,7,8 = equal- R4 B7 k' Z) ]

! t5 d9 J0 h: eRound 28 P6 j5 t* j7 m, o
9,10 vs 11,12 = 9,10 < 11,12
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2 ~5 v; x* {5 t7 ?2 Y9 j: MRound 32 E; ^& {2 b2 \
9 vs 10 = 9 > 109 ~9 d! g2 ^1 J* y2 `2 u
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The answer is 10.
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e.g. #2 假設7為較輕的一粒
6 o& T( l& d% i* o# @' X) Y" L3 {2 TRound 1
" e5 i) x% ?( B8 u/ }3 `2 \* b, g1,2,3,4 vs 5,6,7,8 = 1,2,3,4 > 5,6,7,8
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1 R% ]8 s& |9 a  |( J0 C3 _Round 2
6 I" e6 c2 l5 m9 j2 H5,6 vs 7,8 = 5,6 > 7,89 g$ r! \6 b& Z# m4 b! }% A, W7 K
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Round 3
5 `9 f, l: a# e8 T" X7 vs 8 = 7 < 8
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/ d0 G+ L0 T) [; EThe answer is 7.
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e.g. #3 假設13為較輕的一粒  J/ Q1 B( m  \% |. ^
Round 13 ]' c" z3 X% c! L
1,2,3,4 vs 5,6,7,8 = equal
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8 u! M- m8 K; v7 U3 _# KRound 2- W. ?2 J& K! I3 r+ r
9,10 vs 11,12 = equal
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# T- E/ j1 M3 k0 s% yNo Round 3( Q. ^% x1 y1 k" i4 u( I% n

( x9 M$ e& H- XThe answer is 13.# j. i4 l0 O' K% q% D

0 |, j  J# I- h  \3 }; h唔知我答得正唔正確呢?!
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& A% p6 Z4 n$ m, C7 c% v[ Last edited by hello1997 on 2007-3-2 at 12:39 AM ]