GWD Math 1-25

bigbull

    

I don't know how to solve this problem. Any ideas? Thanks a lot!

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

sarahzhensh

答案是A吗？我用的是列举法，最矮的人一定是一排左边第一，最高的一定是二排最右边，其余的人只能一一列举。

好像没有更好的方法了。