Q. There are $n$ letters and $n$ addressed envelopes, the probability that all the letters are not kept in the right envelope, is
A) $\frac{1}{n!}$
B) $1 - \frac{1}{n!}$
C) $1 - \frac{1}{n}$
D) $n!$
Explanation
(b)
Required probability$= 1 - P$(all letters in right envelope)
$= 1 - \frac{1}{n!}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.