Three couples go to the movie theater. They want to seat people together for maximum enjoyment, but instead they randomly file into a row with six seats. What is the probability that they sit in a socially optimal configuration, in which each person is sitting next to his or her partner?
There are 3! ways to sit the partners,then for each of these there are 2 ways to sit the couples. that is 2^3
so that is 3!*8=48 ways
Another way to look at it is
there are 6 people to chose from for the first seat
the spouse sits next to them
there are 4 people for the next seat
the spouse sits next to them.
there are 2 people left
the spouse sits last.
number of ways = 6*1*4*1*2*1 = 48 ways