SOLUTION: In how many ways can a group of 5 boys and 5 girls be seated in a row of 10 seats if boys and girls must alternate in the row?

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Question 270349: In how many ways can a group of 5 boys and 5 girls be seated in a row of 10 seats if boys and girls must alternate in the row?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
There are only 2 ways if you don't care which girls and which boys
sit in which seats:
(1)
boys: seats 1,3,5,7,9
girls: seats 2,4,6,8,10
and
(2)
swap the boys and girls
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If you want all possible orders of boys and girls
(1)
5%2A4%2A3%2A2%2A1+=+120 ways that 5 boys can sit this way
also 120 ways the girls can sit
(2)
also 120 ways for boys
and 120 ways for girls
------------------------------
In case (1), each of the 120 ways the boys can sit
can be matched with 120 ways the girls can sit
120%2A120+=+14400
The same is true for case (2)
120%2A120+=+14400
The total possible seating arrangements is:
14400+%2B+14400+=+28800