作者moli1984 (ME LLAMO VICENTE)
看板GMAT
标题[问题] PP2 DS195
时间Sat Oct 25 00:56:52 2008
195. 18858-!-item-!-187;#058&012264
If w, x, y, and z are integers such that w/x and y/z are integers
, is w/x + y/z odd?
(1) wx + yz is odd.
(2) wz + xy is odd.
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答案是B
但我不能理解A选项的理由:
suppose wx is odd,
either w or x or both could be odd. If w and x are both
odd, w/x is odd. If w is even and x is odd, w/x is even.
如果wx是奇数 那 w & x不是都应为奇数吗?
谢谢各位板友~
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1F：推 Vinicks:either A or B or C意思是说 是A 是B 也是 C... 10/25 01:03
2F：→ Vinicks:不用写这麽绕口.简单来说就是W是odd, X是odd, W.X也是oodd 10/25 01:04
3F：→ moli1984:那为啥(A)不充分啊~@@~ 10/25 21:41