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Perms and Combs help :) (1 Viewer)

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Jun 26, 2016
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Hey everyone! Thanx in advance :)

Q. Four boys and four girls sit around two concentric circles such that there are four in each circle. In how many ways can they be seated if:

1. There are no restrictions?

2. Three particular boys do not sit together?
 

bujolover

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Jan 5, 2017
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Hey everyone! Thanx in advance :)

Q. Four boys and four girls sit around two concentric circles such that there are four in each circle. In how many ways can they be seated if:

1. There are no restrictions?
I'm only attempting this one for now, because I can't be bothered to do the second one lol.
Fix one person in one of the four seats of one of the circles. Then, 7*6*5 for the other three seats.
Fix one person in one of the four seats of the other circle. Then, 3*2*1 for the other three seats.
So answer = 7*6*5*3*2*1 = 1260.

I might be wrong, so forgive me if I am. This is actually one of my weaker maths topics.
 

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