求教几道GWD30数学题

sophialy2008

Q18:

Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.  By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?



A.     k/m %

B.     (k-m) %

C.     [100(k-m)]/(100+k) %

D.     [100(k-m)]/(100+m) %

E.      [100(k-m)]/(100+k+m) %

这题目意思我楞是绕不过来啊，大虾们帮忙啊Q2:

A certain characteristic in a large population has a distribution that is symmetric about the mean m.  If 68 percent of the distribution lies within one standard deviation d
of the mean, what percent of the distribution is less than m + d ?
                                     

A.     16%

B.     32%

C.     48%

D.     84%

E.      92%

这题是无从下手

Q2:

A certain characteristic in a large population has a distribution that is symmetric about the mean m.  If 68 percent of the distribution lies within one standard deviation d
of the mean, what percent of the distribution is less than m + d ?
                                     

A.     16%

B.     32%

C.     48%

D.     84%

E.      92%

这题是无从下手

Q29:

The toll for crossing a certain bridge is $0.75 each crossing.  Drivers who frequently use the bridge may instead purchase a sticker each month for $13.00 and then pay only $0.30 each crossing during that month.  If a particular driver will cross the bridge twice on each of x days next month and will not cross the bridge on any other day, what is the least value of x for which this driver can save money by using the sticker?



A.     14

B.     15

C.     16

D.     28

E.      29

Q4:

If the average (arithmetic mean) of positive integers x, y, and z
is 10, what is the greatest possible value of z ?


A.     8

B.     10

C.     20

D.     28

E.      30



貌似有点多， 请求各位高手帮我看看把

不胜感激啊

alohawilliam

29道是b么？

sophialy2008

是啊 怎么做出来的

alohawilliam

是啊 怎么做出来的

-- by 会员 sophialy2008 (2009/11/14 14:13:35)

买了月票就是每过桥一次赚0.45元嘛
用13去除0.45算出来是28.08好像，所以14天是不够的，最少也要15天

sophialy2008

是啊 怎么做出来的

-- by 会员 sophialy2008 (2009/11/14 14:13:35)

买了月票就是每过桥一次赚0.45元嘛
用13去除0.45算出来是28.08好像，所以14天是不够的，最少也要15天

-- by 会员 alohawilliam (2009/11/14 14:16:22)

啊 ！！这样的啊， 好像明白了， 谢谢啦

heavennancy

第一个题目的答案处得很变态啊。因为题目里面的k，m都是百分号下的，所以答案里补出了%，所以极其诡异的答案

p2=(1+k%)P    E2=(1+m%)E

rate=(p2/E2-p/E)/(p/E)
     =(1+k%)/(1+m%)-1
     =(k%-m%)/(1+m%)
     =[100(k-m)]/(100+m) %  是D吧

alohawilliam

第一个题目的答案处得很变态啊。因为题目里面的k，m都是百分号下的，所以答案里补出了%，所以极其诡异的答案

p2=(1+k%)P    E2=(1+m%)E

rate=(p2/E2-p/E)/(p/E)
     =(1+k%)/(1+m%)-1
     =(k%-m%)/(1+m%)
     =[100(k-m)]/(100+m) %  是D吧

-- by 会员 heavennancy (2009/11/14 14:44:24)

/agree

sophialy2008

难怪我怎么也绕不过来， 答案就是D啊， 谢谢啊

sayysong

#18  D
Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.  By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?
设原来的每股价格是P，原来的每股收益是E，那么原来的每股价格/每股收益为 r1 = P/E
现在每股价格涨了k%，即（1+k%）P，现在的每股收益为（1+m%）/E，现在的每股价格/每股收益为 r2 = （1+k%）P/（1+k%）M
要求的是increase的ratio，即 （ r2 - r1 ） / r1 = ( k - m ) / ( 100 + m)，做一下百分比换算，就得到D了。

sophialy2008

#18  D
Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.  By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?
设原来的每股价格是P，原来的每股收益是E，那么原来的每股价格/每股收益为 r1 = P/E
现在每股价格涨了k%，即（1+k%）P，现在的每股收益为（1+m%）/E，现在的每股价格/每股收益为 r2 = （1+k%）P/（1+k%）M
要求的是increase的ratio，即 （ r2 - r1 ） / r1 = ( k - m ) / ( 100 + m)，做一下百分比换算，就得到D了。

-- by 会员 sayysong (2009/11/14 14:50:30)

谢谢大牛们 呵呵