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2 couples.

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2 couples.

by sumitkhurana » Wed Feb 18, 2009 10:00 pm
TWO couples and a single person are to be seated on 5 chairs such that no couple is seated next to each other. What is the probability of the above??

1. 1/5
2. 2/5
3. 3/5
4. 4/5
5. 3/7
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by sjd00d » Wed Feb 18, 2009 11:27 pm
IMO 4/5

Take each couple as a group and thus, there are 2X2X3! (3! ways to arrange 2 couples and a single and the 2X2 represents internal arrangement for each couple) ways to have the couples be together...

thus 5! - 2X2X3! = 96 ways to have them separate

thus 96/120 = 4/5
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by bluementor » Thu Feb 19, 2009 3:54 am
https://www.beatthegmat.com/war-of-the-r ... 12457.html

OA is 2/5
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