hello1997

分3組4隻波子秤1 |9 l: X* a' d; U7 v
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Group A: 1,2,3,4
( e# H3 n4 f2 P4 [+ L% NGroup B: 5,6,7,83 U; }0 i' U) Q4 b/ y+ b
Group C: 9,10,11,12' Y; f: @! t5 E5 i
Group D: 13
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6 V6 u* t( x8 W$ aRound 1
! r: K$ D  k  v- y" c1 M- TGroup A vs Group B
- n& U# l9 n" e2 A) ]如A and B一樣, 即較輕一粒在Group C or D
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; C1 B/ n4 [$ N& ^8 JRound 2
1 e1 D  a$ r' _1 x8 W7 t8 h8 Y8 u再在Group C拆成:
/ V+ w1 w& s: I$ ZGroup Ca: 9,105 [+ o* B+ a- p9 k
Group Cb: 11,122 V$ K* q4 T5 U( Q. t0 Z6 @. ]6 V
然後再秤, 如一樣, 即13為較輕一粒.6 u. F( \7 [% p$ q

1 p# J' C; k$ k. w, }' o如不同, 即較輕一組有一粒較輕波子在其中,
% d1 l% B; o/ v# H, W4 k要再秤, Round 3, 之後便知答案.
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* v" ]' N8 m/ S+ l+ \8 F; O9 Z% R. Ke.g. #1 假設10為較輕的一粒
; B+ e0 o# D' c8 DRound 1
! e* T% ~$ \; ~1,2,3,4 vs 5,6,7,8 = equal
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Round 2. s7 E6 @/ Z; I8 i7 `0 E# R
9,10 vs 11,12 = 9,10 < 11,12# v/ M, g: N) r& O6 O

4 i5 c! Q& I0 I3 n: a9 wRound 3, X2 i5 B: n& ~1 }1 M  d
9 vs 10 = 9 > 10
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The answer is 10.
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* L, k' y* p* w4 p7 }& u) ~e.g. #2 假設7為較輕的一粒
9 x+ n- u8 S/ e3 Q8 X2 u" D$ pRound 1
1 U; E5 j( b1 u- Z( |1,2,3,4 vs 5,6,7,8 = 1,2,3,4 > 5,6,7,8  k0 k, Y$ f3 ~) I" d' Y

. R, @4 c7 u5 F" fRound 2. E# J# b3 B% |/ k5 ~6 I
5,6 vs 7,8 = 5,6 > 7,8
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. H5 [3 d: {4 [; M( x) |" L1 yRound 3
) u5 }9 h# M) V$ f# x: K7 vs 8 = 7 < 8
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3 Q, }# L' e; f. ~The answer is 7.
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( M/ d3 k/ S  W$ S, ^2 @e.g. #3 假設13為較輕的一粒
5 E- r8 L2 e1 r" G1 rRound 1
5 H5 ]$ E6 A' n7 q& C1,2,3,4 vs 5,6,7,8 = equal( F! D+ w0 Y' b* z  ?1 N
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Round 24 t6 E; G0 s7 z& C8 B
9,10 vs 11,12 = equal
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No Round 3
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The answer is 13.
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/ x( k; A- l, O# Z2 a# p唔知我答得正唔正確呢?! 7 i9 K4 P* n5 P

4 m2 a+ m  I+ v. F( o% k[ Last edited by hello1997 on 2007-3-2 at 12:39 AM ]