贰凌咦咦 咦约吴日 数学会议

lpilikeit

larryywddd同学好勤劳好好心。。。考完就来贡献了

AllieAn

我是小安，哈哈，L是好人，感谢你~另外，别捏死我~

sdcar2010

1 DS  XY>XZ?

(1) X^2*y>X^2*Z

(2) X^3*y>X^3*Z

1) y>z. But we don't know the sign of x.  Insufficient.
2) xy>xz bingo.  Sufficient


Choose B.

sdcar2010

What is the greatest number for n such that 2^n divides 8!/2！ ?
我的最后一道题 很明确

8!/2! = 2^3*2*2^2*2/2 = 2^6

n = 6

On a side note, if you pay attention to my GMAT challenging question of this one:

"GMAT 数学题（7）

n 为正整数。问 n 最大为多少能让 (2^6)! 整除 2^n ？"

you would have a very easy time to solve the real GMAT question!

Because the question basically hinges on the question "n 为正整数。问 n 最大为多少能让 (2^3)! 整除 2^n ？"

We know the answer to the above question is 2^3 -1 = 7.  Then since the question is asking "n 为正整数。问 n 最大为多少能让 (2^3)! /2! 整除 2^n ？", we simply minus 1 from 7 and you got 6!

nancyxoxo

鸡狗同笼 但是告诉你 80条腿
麻烦ＬＺ　这道题问什么？