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?	Choose one:	A) 5	B) 6	C) 9	D) 24	E) 36
list the people as 1,2,3,4,5,6 from shortest to tallest   First row leftmost -&gt; Only 1 choice - the shortest -&gt; Person 1   Last row rightmost -&gt; only 1 choice - the tallest -&gt; Person 6   First row second seat -&gt; cannot be 4 or 5 because the constraint set on the second row would be violated. So First row second seat has to go to 2 or 3 (2 choices)   First row last seat -&gt; If person 2 is seating on first row second seat, then the first row last seat can be person 3, person 4 or person 5 (3 choices)   First row last seat -&gt; If person 3 is seating on the first row second seat, then the first row last seat can only be 4 or 5 (2 choices).   once we fix the first row, the last row can only be 1 certain choice in order to fit the constraint set by the question.   So we end up with   1,2,3/4/5 -&gt; 3 ways   1,3,4/5 -&gt; 2 ways   Total 5 ways.   5nswer: 5.
<result>A</result>
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?