How many methods are possible for 10 persons to sit in a round table conference, if 2 of them are re

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20 Nov 2012 arrangement

How many methods are possible for 10 persons to sit in a round table conference, if 2 of them are restricted to sit together. Notation ! is factorial means for ex: 4! = 4*3*2*1

OPtion

1) 9!
2) 8!
3) 2*8!
4) 3*8!
5) 4*8!
6) 4324
7) 10!
8) 10!/2
9) 2*10!
10) none of these

Solution

on taking only 1 out of the 2 who will sit together, total persons will be 9, so methods to make them sit in a round table conference = 8!
now 2 methods for sitting are possible for the 2nd one
so ans: 2*8!

Correct Option: 3 Best Solution (0)