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 ?

Question

mathmath333 · Answer

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

mathmate · Answer

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

mathmath333 · Answer

is answer 0

paki · Answer

Montmort's matching problem....

mathmath333 · Answer

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

amilapsn · Answer

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

mathmath333 · Answer

anyway but the answer given in book is zero.

mathmate · Answer

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.

mathmath333 · Answer

oh lol