A person write `4` letters and addresses `4` envelopes. If the letters are placed in the envelopes at random, then the probability that all letters are not placed in the right envelopes, is

Options

A. a) `1/4`
B. b) `11/24`
C. c) `15/24`
D. d) `23/24`

Explanation

No’s of ways - four letter placed in four envelopes is `4! =24` ways


If all letters go into the right place, then no’s of ways `=1`


Probability of letters placed in the right envelop`=1/24`


Probability of not placed in right envelops`=1−1/24=23/24`


Required probability `=23/24`