John along with his wife,parents and four children of which two are boys and two are girls,put up at a rest house with four bed rooms for a night.There are beds for two persons in each room.If either a couple or two persons of the same sex sleep in a room,what is the chance that Mr and Mrs John will sleep together?
I tried to solve the problem.
Chance that Mr and Mrs John will sleep together=favorable conditions/total conditions=2/total no of ways.
Here,i put 2,because there are 2 couples.But the total number of ways is elusive.Its answer is 1/37.
Please help me get the answer.