Swimming Race - 未名空间MITBBS历史存档

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Swimming Race

Swimming Race# BrainTeaser - 大脑工作室

d*u2007-05-08 07:05

1 楼

Five competitors -- A, B, C, D, and E -- enter a swimming race
that awards gold, silver, and bronze medals to the first
three to complete it.
Each of the following compound statements about the race is false,
although one of the two clauses in each may be true.
1) A didn't win the gold, and B didn't win the silver.
2) D didn't win the silver, and E didn't win the bronze.
3) C won a medal, and D didn't.
4) A won a medal, and C didn't.
5) D and E both won medals.
Who won each of the medals?

h*r2007-05-08 07:05

2 楼

A gold
D silver
c bronze

【在 d**u 的大作中提到】

: Five competitors -- A, B, C, D, and E -- enter a swimming race
: that awards gold, silver, and bronze medals to the first
: three to complete it.
: Each of the following compound statements about the race is false,
: although one of the two clauses in each may be true.
: 1) A didn't win the gold, and B didn't win the silver.
: 2) D didn't win the silver, and E didn't win the bronze.
: 3) C won a medal, and D didn't.
: 4) A won a medal, and C didn't.
: 5) D and E both won medals.

s*d2007-05-08 07:05

3 楼

A won gold, D won silver, C won bronze

【在 d**u 的大作中提到】

s*d2007-05-08 07:05

4 楼

didn't see that:)

【在 h**r 的大作中提到】

: A gold
: D silver
: c bronze

f*q2007-05-08 07:05

5 楼

From Statements 3, we conclude that both C and D either won a medal or
neither of them won.
From Statement 4, we conclude that both A and C either won a medal or
neither of them won.
From Statement 3 and 4, we conclude that the three of them (A,C,D) either
all won medals or none of them won. It is obvious that A,C,D all won medals,
and B and did not.
So, statement 1 is partially true (B did not win the silver). Since the
compound is false but can be partially true, then the first clause (A did
n