求助5道GWD 请大家帮忙啦！拜托了！

xiahuistacy · 发表于 2010-1-6 15:43:56

1.

Six cards numbered from 1 to 6 are placed in an empty bowl. First one card is drawn and then put back into the bowl; then a second card is drawn. If the cards are drawn at random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5 ?

答案是

2

——

5 不好意思本人不会打分数会的同学也可以告诉我哈哈谢谢

2.

A rectangular photograph is surrounded by a border that is 1 inch wide on each side. The total area of the photograph and the border is M square inches. If the border had been 2 inches wide on each side, the total area would have been (M
+ 52) square inches. What is the perimeter of the photograph, in inches?

A. 34

B. 36

C. 38

D. 40

E. 42

这个题目答案是D 但是我算出来的是44 没有答案哈哈我也不知道为什么会这样请大家指教

3.

150, 200, 250, n

Which of the following could be the median of the 4 integers listed above?

I. 175

II. 215

III. 235

A. I only
B. II only

C. I and II only
D. II and III only
E. I, II, and III
这个题目选C 但是我觉得应该是A呀请大家帮忙

4.

The operation Θ is defined by x Θ y
= + for all nonzero numbers x and y. If z is a number greater than 1, which of the following must be true?

I. x
Θ (-z) = 0
II. z Θ
= 1
III. Θ
= z

A. I only
B. I and II only

C. I and III only
D. II and III only
E. I, II, and III
这个题目答案说是E 但是我觉得应该是D 我怎么都觉得条件一不对

5.

In a meeting of 3 representatives from each of 6 different companies, each person shook hands with every person not from his or her own company. If the representatives did not shake hands with people from their own company, how many handshakes took place?

A. 45

B. 135

C. 144

D. 270

E. 288

这个题目答案是B 我完全不会请大家帮忙

马上就二战了谢谢大家了 CD‘s 万岁

冷咖啡 · 发表于 2010-1-6 15:59:45

1.

Six cards numbered from 1 to 6 are placed in an empty bowl. First one card is drawn and then put back into the bowl; then a second card is drawn. If the cards are drawn at random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5 ?

一共六个cards，随意取2个，共有c(2,6)种取法=15
和为8的组合有 2、6， 3、5， 4、4， 6、2， 5、3， 4、4 六种，所以答案是2/5

冷咖啡 · 发表于 2010-1-6 16:07:42

A rectangular photograph is surrounded by a border that is 1 inch wide on each side. The total area of the photograph and the border is M square inches. If the border had been 2 inches wide on each side, the total area would have been (M
+ 52) square inches. What is the perimeter of the photograph, in inches?

(a+2)(b+2)=M -------1

(a+4)(b+4)=m+52 --------2
方程2-方程1 2a+2b+12=52
所以选D

冷咖啡 · 发表于 2010-1-6 16:14:01

3.

150, 200, 250, n

Which of the following could be the median of the 4 integers listed above?

如果n小于150，则中数是175
如果中数是215，n=230 即可
无论如何，中数最大只能为225，因为只能是200 和 250的平均

mydloveal · 发表于 2010-1-6 16:17:01

1题楼上答了

2.设photograph的长宽分别是a,b 则(a+2)*(b+2)=M (a+4)*(b+4)=M+52 两式相减可以算出a+b=20 周长就是40了（44我也不知道你怎么算出来的- -是不是有个方程没考虑两边都有边框

mydloveal · 发表于 2010-1-6 16:27:37

4.x Θ y= + 。。。。= + 是说结果是正数？还是什么……没看懂

5. 3*（18-3）*6=270 再除以2 是135 。
排列组合~每个公司的每个人和其他15个人握手~一共6个公司。
得出的270有交叉重复，所以除以2 （私以为这个题有点问题- -！题目没说once之类不能重复的词……）

求助5道GWD 请大家帮忙啦！拜托了！

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求助5道GWD 请大家帮忙啦 ！拜托了！

所属分类: GMAT考试

正在浏览此版块的会员 ()

求助5道GWD 请大家帮忙啦！拜托了！