Re: Plz solve diss..

Posted by amianand on Jun 24, 2015; 4:00pm
URL: http://discussion-forum.276.s1.nabble.com/Plz-solve-diss-tp7598374p7598406.html

My interpretation of question is that none of the persons are sitting on adjacent seats. Though it can also be that no 2(particular 2) are not sitting together. In that way question is not clear. Anyways, Consider, you have to select n seats from 2n seats such that none of selected seats are together. So, you dont have to select n seats, there will be n+1 gaps between these n seats. Select n gaps out of these n+1 gaps and place your remaining n seats here. i.e. C(n+1,n).n!/C(2n,n).n! = (n+1)/C(2n,n)