GWD-1的排列组合题2

anita_tian

 

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
E. 36

:-Dの

排列组合题是挺恐怖的

anita_tian

 呵呵,真的是只有这种方法啊,我当时就是一个一个排的,还想有什么简单的方法可以计算呢

可怕的排列组合题,只要稍微难点,碰上一准死

James

题目我不翻译了 大概就是6个人两排 每个人要比前面的人高 每一排还必须右边的比左边的高

 

这个题目严格来说很难用真正的排列组合思维来做

并且这道题也是历年来GMAT考试中绝无仅有的一道难题

 

这个题目最简捷的办法就是枚举法 也就是把这些东西都排出来：我们用123456表示6个人

 

A

456

123

 

B

356

124

 

C

256

134

 

D

246

135

 

E

346

125

 

如上5种