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.

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