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题库 / Prep2007E2-DS-137
If x and y are positive integers, is xy a multiple of 8 ?
(1) The greatest common divisor of x and y is 10.
(2) The least common multiple of x and y is 100.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
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如果x取了2*2，y取了5*5，那xy没有三个2，所以不会是8的倍数。但是如果x取了2*2，y取了2*5*5，那就有三个2了，会是倍数。insufficient.
两个结合：根据条件1给出的m，n，结合第二点，那m，n一定是要从2，5，2，5中挑选的。但是又不能有公因子。所以m，n只能一个挑2，另外一个挑5，所以x，y分别是，2*2*5，5*2*5，所以xy一定是8的倍数
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