求PREP-DS-2-137 解

137.
                14447-!-item-!-187;#058&010361

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.

答案:C

我觉得1+2好象得出的结论是XY不是8的倍数, 那么这样的情况不选E吗? 困惑中....

gcd(x, y) * lcm(x, y) = xy

所以，由1+2可得xy=1000