prep ds1中关于集合的错题特来请教

maomm

45.       3906-!-item-!-187;#058&003579

How many of the 42 people in a group are employed students?

 

(1)  29 of the 42 people are employed.

 

(2)  24 of the 42 people are students.

 

 e，是因为没有交待42人中只有EMPLOYED和STUDENTS两类人吗？

 

64.       5320-!-item-!-187;#058&004563

Are at least 10 percent of the people in Country X who are 65 years old or older employed?

 

(1) In Country X, 11.3 percent of the population is 65 years old or older.

 

(2) In Country X, of the population 65 years old or older, 20 percent of the men and 10 percent of the women are employed.

 b，根据B只能说明65岁以上的人口中，男人中有20%，女人中有10%，是工作的。但是也证明不了至少有10%的人口是65以上且有工作呀？

 

120.     12140-!-item-!-187;#058&008146

How many of the students in a certain class are taking both a history and a science course?

 

(1)  Of all the students in the class, 50 are taking a history course.

 

(2)  Of all the students in the class, 70 are taking a science course.

C,e，是因为没有说明班上学生只可能参加要么历史，要么科学课吗？

 

164.     16412-!-item-!-187;#058&010774

At a two-day seminar, 90 percent of those registered attended the seminar on the first day.  What percent of those registered did not attend the seminar on either day?

 

(1)  A total of 1,000 people registered for the two-day seminar.

 

(2)  Of those registered, 80 percent attended the seminar on the second day.

 e，这题没有思路

 

 

165.     16466-!-item-!-187;#058&010795

Of the 1,400 college teachers surveyed, 42 percent said that they considered engaging in research an essential goal.  How many of the college teachers surveyed were women?

 

(1) In the survey, 36 percent of the men and 50 percent of the women said that they considered engaging in research an essential goal.

 

(2) In the survey, 288 men said that they considered engaging in research an essential goal.

 

 a, B为什么不对呢？

192.     18939-!-item-!-187;#058&011984

Of the 75 houses in a certain community, 48 have a patio.  How many of the houses in the community have a swimming pool?

 

(1) 38 of the houses in the community have a patio but do not have a swimming pool.

 

(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

 b，我觉得A是对的，设二者都有的为X，则48+X-10=75，

 

 

202.     19528-!-item-!-187;#058&012279

Each employee of Company Z is an employee of either Division X or Division Y, but not both.  If each division has some part-time employees, is the ratio of the number of full-time employees to the number of part-time employees greater for Division X than for Company Z ?

 

(1) The ratio of the number of full-time employees to the number of part-time employees is less for Division Y than for Company Z.

 

(2) More than half of the full-time employees of Company Z are employees of Division X, and more than half of the part-time employees of Company Z are employees of Division Y.

B,d，没有思路。

 thanks a ton!!!!!!!!!!!!

mymengming

以下是引用maomm在2008-5-24 2:39:00的发言：

45.       3906-!-item-!-187;#058&003579

How many of the 42 people in a group are employed students?

(1)  29 of the 42 people are employed.

(2)  24 of the 42 people are students.

e，是因为没有交待42人中只有EMPLOYED和STUDENTS两类人吗？
                

利用表格解题

	S	US
E	??		29
UE
	24		42

 

 

64.       5320-!-item-!-187;#058&004563

Are at least 10 percent of the people in Country X who are 65 years old or older employed?

(1) In Country X, 11.3 percent of the population is 65 years old or older.

(2) In Country X, of the population 65 years old or older, 20 percent of the men and 10 percent of the women are employed.

 b，根据B只能说明65岁以上的人口中，男人中有20%，女人中有10%，是工作的。但是也证明不了至少有10%的人口是65以上且有工作呀？
                

  你理解错句子的意思了

Are at least 10 percent of the people in Country X （who are 65 years old or older） employed?

按照你的那个解释，这个句子就没有谓语了

答案是B

120.     12140-!-item-!-187;#058&008146

How many of the students in a certain class are taking both a history and a science course?

(1)  Of all the students in the class, 50 are taking a history course.

(2)  Of all the students in the class, 70 are taking a science course.

C,e，是因为没有说明班上学生只可能参加要么历史，要么科学课吗？
                

  还是画图
    

	H	UH
S	??		70
US
	50

答案是E

164.     16412-!-item-!-187;#058&010774

At a two-day seminar, 90 percent of those registered attended the seminar on the first day.  What percent of those registered did not attend the seminar on either day?

(1)  A total of 1,000 people registered for the two-day seminar.

(2)  Of those registered, 80 percent attended the seminar on the second day.

 e，这题没有思路
                

  由于不知道两天registered人的重合程度，所以不能判断有多少人注册了，但是没有上一次课的 

答案是E

165.     16466-!-item-!-187;#058&010795

Of the 1,400 college teachers surveyed, 42 percent said that they considered engaging in research an essential goal.  How many of the college teachers surveyed were women?

(1) In the survey, 36 percent of the men and 50 percent of the women said that they considered engaging in research an essential goal.

(2) In the survey, 288 men said that they considered engaging in research an essential goal.

 a, B为什么不对呢？
            

  (2)

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A

192.     18939-!-item-!-187;#058&011984

Of the 75 houses in a certain community, 48 have a patio.  How many of the houses in the community have a swimming pool?

(1) 38 of the houses in the community have a patio but do not have a swimming pool.

(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

 b，我觉得A是对的，设二者都有的为X，则48+X-10=75，
                

  （1）

	P	UP
S	10		??
US	38
	48		75

  答案是B

202.     19528-!-item-!-187;#058&012279

Each employee of Company Z is an employee of either Division X or Division Y, but not both.  If each division has some part-time employees, is the ratio of the number of full-time employees to the number of part-time employees greater for Division X than for Company Z ?

(1) The ratio of the number of full-time employees to the number of part-time employees is less for Division Y than for Company Z.

(2) More than half of the full-time employees of Company Z are employees of Division X, and more than half of the part-time employees of Company Z are employees of Division Y.

B,d，没有思路。
                

 答案是D
    

FX/PX>(FX+FY)/(PX+PY)?
    

（1）
    

FY/PY<(FX+FY)/(PX+PY)
    

化简， FX*PY>FY*PX

如果FX/PX>(FX+FY)/(PX+PY)则有FX*PY<FY*PX,所以得到FX/PX<(FX+FY)/(PX+PY)

如果FX/PX>(FX+FY)/(PX+PY)则有FX*PY<FY*PX,所以得到FX/PX<(FX+FY)/(PX+PY)

得到的回答是NO

（2）

FX/(FX+FY)>1/2   *

PY/(PX+PY)>1/2                     PX/(PX+PY)<1/2   **

*/**     得到FX/PX<(FX+FY)/(PX+PY)

得到的回答也是NO

所以最后的答案是D

 

这个题目有陷阱，不要认为回答的答案是NO就认为是不能得出

maomm

非常感谢MYMENGMING兄弟的详解.其它的我都明白了,就是你画的表格都还得消化一下,因为以前做这类题只是画维恩图,用这种表格没用过,好好学习一下.

非常非常的感谢.

祝你考出理想的成绩

maomm

165.     16466-!-item-!-187;#058&010795

Of the 1,400 college teachers surveyed, 42 percent said that they considered engaging in research an essential goal.  How many of the college teachers surveyed were women?
            

(1) In the survey, 36 percent of the men and 50 percent of the women said that they considered engaging in research an essential goal.
            

(2) In the survey, 288 men said that they considered engaging in research an essential goal.
            

 a, B为什么不对呢？
            

  (2)
                

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A
                        

好心的版主,我理解了你的表格后,反而发现165题的A用表格讲不通了.A说36%MEN和50%WOMEN说他们有G,但是他们各自人数不知,则0.36X+0.5Y=1400*0.42,因此还是求不出Y的数量呀.我思路错哪了,再次感谢.

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A
            

好心的版主,我理解了你的表格后,反而发现165题的A用表格讲不通了.A说36%MEN和50%WOMEN说他们有G,但是他们各自人数不知,则0.36X+0.5Y=1400*0.42,因此还是求不出Y的数量呀.我思路错哪了,再次感谢.

maomm

165.     16466-!-item-!-187;#058&010795

Of the 1,400 college teachers surveyed, 42 percent said that they considered engaging in research an essential goal.  How many of the college teachers surveyed were women?
            

(1) In the survey, 36 percent of the men and 50 percent of the women said that they considered engaging in research an essential goal.
            

(2) In the survey, 288 men said that they considered engaging in research an essential goal.
            

 a, B为什么不对呢？
            

  (2)
                

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A
                        

好心的版主,我理解了你的表格后,反而发现165题的A用表格讲不通了.A说36%MEN和50%WOMEN说他们有G,但是他们各自人数不知,则0.36X+0.5Y=1400*0.42,因此还是求不出Y的数量呀.我思路错哪了,再次感谢.

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A
            

好心的版主,我理解了你的表格后,反而发现165题的A用表格讲不通了.A说36%MEN和50%WOMEN说他们有G,但是他们各自人数不知,则0.36X+0.5Y=1400*0.42,因此还是求不出Y的数量呀.我思路错哪了,再次感谢.

maomm

最后一个更弱的问题就是:

192.     18939-!-item-!-187;#058&011984

Of the 75 houses in a certain community, 48 have a patio.  How many of the houses in the community have a swimming pool?
            

(1) 38 of the houses in the community have a patio but do not have a swimming pool.
            

(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

答案B中的两者都有,和两者都没有在表格中,我不晓得往哪填了.

很笨,非常感谢.

maomm

165题我想出来了,是设被调查的老师有X名女老师.则,1/2X+1400*0.58=X,对吧?

maomm

最后两题,是PREP-DS2中的.

132.     14175-!-item-!-187;#058&010326

If the drama club and music club are combined, what percent of the combined membership will be male?

 

(1)  Of the 16 members of the drama club, 15 are male.

 

(2)  Of the 20 members of the music club, 10 are male.

这题不知道该怎么画图.答案是E,是因为合并后的总人数未知吗?

185.     17987-!-item-!-187;#058&011677

Of the 200 members of a certain association, each member who speaks German also speaks English, and 70 of the members speak only Spanish.  If no member speaks all three languages, how many of the members speak two of the three languages?

 

(1)  60 of the members speak only English.

 

(2)  20 of the members do not speak any of the three languages.

这题题目说:第一个说德语的都会说英语,而条件1说60个人只说英语,那表示画图应该将说德语的包括在英语圈里,则说两种语言的就是说德也说英的,为X,60+X+70-20=200,请问对吗?

thanks a lot!

mymengming

以下是引用maomm在2008-5-24 11:05:00的发言：

165.     16466-!-item-!-187;#058&010795

Of the 1,400 college teachers surveyed, 42 percent said that they considered engaging in research an essential goal.  How many of the college teachers surveyed were women?
   

(1) In the survey, 36 percent of the men and 50 percent of the women said that they considered engaging in research an essential goal.
   

(2) In the survey, 288 men said that they considered engaging in research an essential goal.
   

 a, B为什么不对呢？
   

  (2)
    

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A
      

好心的版主,我理解了你的表格后,反而发现165题的A用表格讲不通了.A说36%MEN和50%WOMEN说他们有G,但是他们各自人数不知,则0.36X+0.5Y=1400*0.42,因此还是求不出Y的数量呀.我思路错哪了,再次感谢.

	W	M
G		288	1400*42%
UG
			1400

只能得到W且G的数量，不能得到W的数量

答案A
      

好心的版主,我理解了你的表格后,反而发现165题的A用表格讲不通了.A说36%MEN和50%WOMEN说他们有G,但是他们各自人数不知,则0.36X+0.5Y=1400*0.42,因此还是求不出Y的数量呀.我思路错哪了,再次感谢.

	W	M
G	50%W	36%M	1400*42%
UG
	W	M	1400

50%W+36%M=1400*42%

W+M=1400

=>W=?

M=?

mymengming

192.     18939-!-item-!-187;#058&011984

Of the 75 houses in a certain community, 48 have a patio.  How many of the houses in the community have a swimming pool?
            

(1) 38 of the houses in the community have a patio but do not have a swimming pool.
            

(2) The number of houses in the community that have a patio and a swimming pool is equal to the number of houses in the community that have neither a swimming pool nor a patio.

 b，我觉得A是对的，设二者都有的为X，则48+X-10=75，
            

  （2）

	P	UP
S	X		??
US		X
	48		75

  答案是B