Tuesday, August 28, 2012

Picking hats

N people come to a room to attend a conference. They leave their hats outside the room. When the conference ended, the people were in a hurry, so they picked one hat each at random, one after another. Given N is considerably large, find the probability that no one gets his/her own hat.

Courtesy : Prof. Sharad Sane, IIT Bombay.


Pratik Poddar said...

Interesting problem.

1/e ?

pathankhan salman said...

Yes it is. By Inclusion exclusion principle.

tarun tari said...

i think its 1-1/e