mathmath333 one year ago There are 6 different letters and 6 correspondingly addressed envelopes. If the letters are randomly put in envelopes ,what is the probablity that exactly 5 letters go into the correct addressed envelope ?

1. mathmath333

\large \color{black}{\begin{align} & \normalsize \text{There are 6 different letters and 6 correspondingly addressed envelopes.}\hspace{.33em}\\~\\ & \normalsize \text{If the letters are randomly put in envelopes ,what is the probablity that}\hspace{.33em}\\~\\ & \normalsize \text{exactly 5 letters go into the correct addressed envelope ?}\hspace{.33em}\\~\\ \end{align}}

2. mathmate

P(5)=0 because it is impossible to have exactly 5 going into the correct envelope. The remaining (sixth) must be correct as well.

3. mathmath333

4. paki

Montmort's matching problem....

5. mathmath333

but the condition when 6 letters are in the correct envelopes also includes 5 letters case.

6. amilapsn

$\href{ https:///www.google.com/search?q=exactly&ie=utf-8&oe=utf-8 }{\Huge\sf Exactly}$

7. mathmath333

anyway but the answer given in book is zero.

8. mathmate

What @amilapsn meant is "what is the probablity that $$\Large exactly$$ 5 letters go into the correct addressed envelope." So 6 letters correctly placed is excluded.

9. mathmath333

oh lol