涛涛GWD31中的GWD3-2~GWD3-33Thanx~~

LilyJune

我翻了讨论贴，题号和我做的gwd为啥对不上呢。。

下面这2题怎解？偶对概率的题目没有什么概念。。。高中偶也没有学。。答案B thanx~

Q2:

On Saturday morning, Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains.  If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday?

 

A.     0.008

B.     0.128

C.     0.488

D.     0.512

E.      0.640

 

还有一道排列组合的题目。。。答案A

Q33:

A photographer
   will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row.  The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her.  How many such arrangements of the 6 people are possible?

 

A.     5

B.     6

C.     9

D.     24

36

hitlzc

做整套的数学题之前可以复习下系统的基础知识。

可以参考QYQ GMAT数学难题精解，下面链接2楼有下载:

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=143895&page=1

hitlzc

另外MM这个题是涛涛版GWD31套中的吧？如是，请注明

再就是如果问多道题，请将题号逐一在标题中标出，谢谢配合！

hitlzc

Q2:
On Saturday morning, Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains.  If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday?
 
A.     0.008
B.     0.128
C.     0.488
D.     0.512
E.      0.640

周一回来，说明周六没下雨，周日没下雨，周一下雨了。

每天下雨的概率是0.2，不下是0.8

所以周一回来的概率就是周六不下雨的概率×周日不下雨的概率×周一下雨的概率＝0.8*0.8*0.2＝0.128

hitlzc

Q33:

A photographer
                will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row.  The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her.  How many such arrangements of the 6 people are possible?

 

A.     5

B.     6

C.     9

D.     24

36

用个笨办法，全举法排一下了。设为1<2<3<4<5<6,按题目条件排了。

LilyJune

以下是引用hitlzc在2006-6-5 16:19:00的发言：

另外MM这个题是涛涛版GWD31套中的吧？如是，请注明

再就是如果问多道题，请将题号逐一在标题中标出，谢谢配合！

 不好意思，忘记说是GWD31了，打字后面一个题号打漏了

LilyJune

以下是引用hitlzc在2006-6-5 16:34:00的发言：

Q33:

A photographer
    will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row.  The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her.  How many such arrangements of the 6 people are possible?

 

A.     5

B.     6

C.     9

D.     24

36

用个笨办法，全举法排一下了。设为1<2<3<4<5<6,按题目条件排了。

有没有可以用排列组合计算的方法呢？偶怕万一遇到个多的，咋办a?

yangxuemei0111

Q33:

A photographer
    will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row.  The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her.  How many such arrangements of the 6 people are possible?

 

A.     5

B.     6

C.     9

D.     24

36

这道题还是不明白呀！！！

ElleWoodsQin

up!!GWD3-33不明白！请NN们讲解一下吧...除了排一下，还有什么办法呢？？

doudoulovely

同样求助谢谢