07年1月math原始机经讨论稿第13篇完(671-753)1.28 23:28

rio

以下是引用seabrook在2007-1-30 7:23:00的发言：

选项B:同时反对A和B的人数是65  等同与

The number of voters who responded “unfavorable” for both candidates was 10.

那不是不应该选吗? 可是688给出的答案是B ???

那B不是可以得出结论吗？

rio

以下是引用lifechaser在2007-1-30 7:24:00的发言：
哪位NN能不能把681.概率题：小姑娘W吃糖果。罐子里面有6颗绿糖，3颗红糖，2颗白糖。每次吃一颗。问，连续两次吃到白糖的概率？
   

2/11*1/10 仔细解释一下啊?多谢了!

第一次吃到白糖：2/11

第二次还吃到白糖：1/10(因为第一次吃掉一个了)

所以相乘

cwcc

728.DS 问能否确定line K 在X-axis 上的intersection 是多少
1） K平行于Y-axis，并且点（3，0）在K上
2） K平行于X-axis ， 并且点（4。0） 在K上ans:A


the second ,if K parally with X axis,and have one point on the X axis,then the K should be the X axis?

cwcc

688  是不是类似GWD里的这道题目? 

	Favorable	Unfavorable	Not Sure
Candidate M	40	20	40
Candidate N	30	35	35

 

The
table above shows the results of a survey of 100 voters each responded
“favorable” or “unfavorable” or “not sure” when asked about their
impressions of candidate M and of candidate N.  What was the number of voters who responded “favorable” for both candidates?

(1)   The number of voters who did not respond “favorable” for either candidate was 40.

(2)
              The number of voters who responded “unfavorable” for both candidates was 10.

                  

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

Answer:    A

    

        

                

        

who can explain this question? thanks a lot!

    

shenyang

以下是引用rio在2007-1-28 21:26:00的发言：

20多岁是一个男人一生最黯淡的时光要什么没什么
所以男人一定要珍惜这个时期爱你的女孩
因为她是在用一生最美好的时光陪你走过你最黯淡的时光

——与各位男士共勉

-------------------------------------------------------

同意，我觉得女士也可以共勉^^不过也许最暗淡的时光是最快乐的时光^^不过天下最难的事情就是永恒~~

还有刚刚下班回家就看到了Rio的回复，谢谢！

好羡慕你的GF^^

shenyang

对于利率那道题，可能我太执著了，数学没怎么复习，要考试了，临时抱佛脚呢^^

我总是对这种文字题型特别不敢冒，所以又仔细看了一下OG对复利的解释：

If interest is compounded, then interest is computed on the principal as well as on any interest already earned. 就是说单利，复利的区别在于本金（基本金）的基准，是利率*原始本金，还是*加了利率之后的本金。

例题也是在math review里的，我把所有的解释都贴一下：

OG11例题(142页）IF $10,000 is invested at 10 percent annual interest, compounded semiannually, what is the balance after 1 year?

Solution:The balance after the first 6 months would be

10,000+(10,000)(0.05)=10,500

the balance after one year would be 10,500+(10,500)(0.05)-11,025

note that the interest rate for each 6-month period is 5%, which is half of the 10% annual rate. The balance after one year can also be expressed as

10,000(1+0.1/2)^2

billni

以下是引用shenyang在2007-1-30 11:34:00的发言：
以下是引用rio在2007-1-28 21:26:00的发言：

20多岁是一个男人一生最黯淡的时光要什么没什么
所以男人一定要珍惜这个时期爱你的女孩
因为她是在用一生最美好的时光陪你走过你最黯淡的时光

——与各位男士共勉

----------------------------------------------------

深有同感！能遇上这样女孩的男人是幸运的，值得好好珍惜！

hollyball

我不同意这句话,20多岁的女生(比如我),

我不认为是人生中最美好的时光.指什么,青春,美貌么??

女生应该和男生一样,有自己的事业,人生的追求,现在的我,什么都还不是......

男生最暗淡的时光也不是这20多岁的时候,我喜欢20多岁的男生,有激情,有梦想,还有宝贵的纯真......即使还没有钱

但我祝福当下的爱人,彼此珍惜!这个世界上,能遇到爱的人,就是一件幸福的事情.

sweetlychee

math-->男女生-->爱-->人生...哈哈.

sweetlychee

以下是引用shenyang在2007-1-29 2:48:00的发言：

687在pp中找到原题可是不知道怎么贴上去，就敲给大家吧：

The figure shown represents a board with four rows of pegs, and at the bottom of the board are four cells numbered 1 to 4. Whenever the ball shown passes through the opening between two adjacent pegs in the same row, it will hit the peg diredtly beneath the opening. The ball then has probability 1/2 of passing through the opening immediately to the left of that peg and probability 1/2 of passing through the opening immediately to the right. whtat is the probability that when the ball passes throuhg the first two pegs at the top it will end up in cell2?(3/8)

图可以参考687。

我请大家方便,再讨论一下JJ687题吧,我觉得JJ687和PP上的这题并不完全相同.看黄色所标,落点就不一样.我画了好几次图,JJ687的答案都是1/8.晕help me!