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标题: 求教：ttGWD 09-Q32 [打印本页]

作者: hellcomer 时间: 2006-8-11 22:26
标题: 求教：ttGWD 09-Q32

如何证明不是C?

Q32:

What is the remainder when the positive integer x is divided by 8?

(1) When x is divided by 12, the remainder is 5.

(2) When x is divided by 18, the remainder is 11.

作者: caterpillarcn 时间: 2006-8-11 23:06

最小公倍数是36，然后求出两个条件给的数，方法如下，
12a+5=18b+11， so a=2 we can get x, x=29+36n(n=integer) 29 divided by 8, remainder is always 5
but if 36n is divided by 8, there are two possible remainders, 4 and 0.

combined the above,we know that the ultimate remainder is not fixed, it's can be either 1 or 5.

其实不用求出29，只看12和18的最小公倍数的倍数就可以知道，36n/8的remainder不是恒定的，所以X/8的也不是

作者: hellcomer 时间: 2006-8-11 23:55
thanks.

作者: may08131 时间: 2010-9-3 13:16
看不懂诶。。。。哪位能解释再清楚丫。。。。。。。

作者: 双鱼游 时间: 2010-9-23 18:02
你看这个帖子，http://forum.chasedream.com/GMAT_Math/thread-51193-1-1.html，求余数的通用方法

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