GWD3-Q20

oasis777

GWD3-Q20:
Shipping Clerk:  The five specially ordered shipments sent out last week were sent out on Thursday.  Last week, all of the shipments that were sent out on Friday consisted entirely of building supplies, and the shipping department then closed for the weekend.  Four shipments were sent to Truax Construction last week, only three of which consisted of building supplies.
If the shipping clerk’s statements are true, which of the following must also be true?
A.    At least one of the shipments sent to Truax Construction last week was specially ordered.
B.    At least one of last week’s specially ordered shipments did not consist of building supplies.
C.    At least one of the shipments sent to Truax Construction was not sent out on Thursday of last week.
D.    At least one of the shipments that were sent out on Friday of last week was sent to Truax Construction.
E.    At least one of the shipments sent to Truax Construction last week was sent out before Friday.
希望能给解释

VincentShu

题目中有四个条件：
1、5艘OS礼拜四出发。（没有说只有这些是OS的）
2、星期五出发的船把全部有BS。（就是说，星期五出发的一定都有BS，但是有BS的不一定是星期五出发的。）
3、有四艘船到了TC，只有三艘是有BS的。
4、礼拜五之后就没有船出发了。（the shipping department then closed for the weekend）
（注意：上述条件的船是可以重合的，如：有一艘船是OS的，又是装了BS的，也到达了TC）

A。至少有一艘到达TC的船是OS的。（这些船可以都不是OS的）
B。至少有一艘OS的船不含BS。（可以一艘都没有，如：星期五出发的都是装有BS（限定）但是没有OS的）
C。至少有一艘到达TC的船不是礼拜四出发的。（首先装BS的三艘肯定不是，其次还有一艘可以剩下的任意一天出发，不一定是礼拜四）
D。至少有一艘星期五出发的船是去TC的。（也可以一艘都没有）
E。至少有一艘到达TC的船是礼拜五前出发的。（很明显，星期五出发的都是有BS的。所以剩下一艘可以星期五之前的任何一天出发，同C）

感觉排除法应该是最好考虑，也最保守的方法吧，must be ture问题方法欢迎讨论！

cici_head2A

VincentShu 发表于 2011-12-25 16:13
题目中有四个条件：1、5艘OS礼拜四出发。（没有说只有这些是OS的）2、星期五出发的船把全部有BS。（就是说 ...

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