作者onznka (任性˙小鬼头)
看板GMAT
标题Re: [问题] PP2-DS-80
时间Sat Mar 8 22:48:29 2008
※ 引述《spplen (起步向学走)》之铭言：
: 问题如下：
: If x and y are positive integers such that x = 8y + 12, what is the greatest
: common divisor of x and y ?
: (1) x = 12u, where u is an integer.
: (2) y = 12z, where z is an integer.
: ans.B
: 麻烦解答了!谢谢!
(1)
x=12u ==> 12 u = 8y + 12 ==> y = [ 12 (u-1) ] / 8 ==> 不充分
(2)
y=12z ==> x = 8 (12z) + 12 ==> x = 12 ( 8z + 1 ) ==> 充分
可知 where z is an integer , x y the greatest common divisor 为12
如果有错 请见谅^^"
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◆ From: 61.228.212.114
※ 编辑: onznka 来自: 61.228.212.114 (03/08 22:48)
1F：→ spplen:谢谢o大! 03/09 11:28
2F：推 romu:了解，感谢o大，没仔细看真的完全不知道题目在说什麽XD 03/09 21:12