Sunday

April 20, 2014

April 20, 2014

Posted by **Rey** on Sunday, February 27, 2011 at 5:25am.

- Permutation -
**drwls**, Sunday, February 27, 2011 at 6:09amClearly they must alternate boy-girl-boy-girl etc. So the question becomes: How many ways can that be done?

Consider chair #1. If a boy goes there, there are 5 possibilities. Then there are 5 for the next chair (any girl), then any of four boys, etc until you get a number of permutations of 5!*5! = 14,400

If chair #1 starts with a girl, then there are 14,400 more possible permutations. That is a total of 28,800

If you are only interested in the sequence of people and not who sits on chair #1, then you must divide by 10, giving 2880.

- Permutation -
**Sniper**, Sunday, February 27, 2011 at 6:22amLets arrange the 5 girls first, fixing 1: (5-1)! = 4! = 24 .

Then arrange 5 boys = 5! = 120

so, total arrangements required: 120 x 24 = 2880

**Related Questions**

Math - If the ratio of girls to boys on the swim team is 2:3, which of these ...

Math Repost - There are 5 boys and 4 girls in my class. In how many ways can ...

Math - Mrs.Smith's class has 12 girls and 8 boys. What percent of he class are ...

Math - If the ratio of girls to boys on the track team is 5 to 6 which of these ...

psychology - Researchers have found that, during childhood: A) girls' gender ...

math - There are 5 boys and 4 girls in my class. In how many ways can they be ...

math - In how many ways can 4 boys and 4 girls sit around a circle table if each...

English Expression - A: How many boys and girls are there in the park? B: There ...

MATH - URGENT!!! - There are 5 boys and 4 girls in my class. In how many ways ...

math - there were 490 altogether in 2 groups. group A consited of only boys and ...