求教一道机经题

wwc008love · 发表于 2012-3-11 11:21:32

狗主回忆的版本信息貌似有误，下面是GWD原题，请大家看一下哈！
When positive integer x is divided by 5, the remainder is 3; and when x is divided by 7, the remainder is 4. When positive integer y is divided by 5, the remainder is 3; and when y is divided by 7, the remainder is 4. If x > y, which of the following must be a factor of x - y?

A.12 B.15 C.20 D.28 E.35
答案：x=18,53,88,123,...,35n+18，答案选E
这题的思路是啥

michelleqi · 发表于 2012-3-11 11:28:46

X=5a+3=7b+4
Y=5c+3=7d+4

X-Y=5(a-c)=7(b-d)

故能被5和7整除，5*7=35

merrymenglu · 发表于 2012-3-11 11:33:11

我用列举的办法诶~~ 虽然很笨..但是通用

wwc008love · 发表于 2012-3-11 12:36:33

谢。说的很明白

求教一道机经题

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块