[計量] A photographer will arrange 6 ...
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 peoploe within each row must
increase form left to right, and each person in
second row must be taller than 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
Ans: A
我只會一種一種數。
請問有沒有快一點的想法或算法？
麻煩大家了，謝謝。
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