Q2

[john_haddock]

Tanya prepared 4 different letters to be sent to 4 different addresses. For each letter she prepared an envelope with its correct address. If the 4 letters are to be put into the 4 envelopes randomly, what is the probability that only 1 letter will be put in the envelope with the correct address?

1/24
1/8
1/4
1/3
3/8

[stock.mojo11]

Tanya prepared 4 different letters to be sent to 4 different addresses. For each letter she prepared an envelope with its correct address. If the 4 letters are to be put into the 4 envelopes randomly, what is the probability that only 1 letter will be put in the envelope with the correct address?

1/24
1/8
1/4
1/3
3/8

Was discussed here in length post5773.html

total number of ways of arranging 4 letters in 4 envelopes = 4 X 3 X 2 X 1 (denominator)

One letter in correct env Can be any of the 4 right. so 4 ways

Now 3 letters and 3 env. all should go into wrong env

in first env you can pu one of the two wrong letters. then left with 2 letters and 2 envelopes. you can put those in 1 way. Hence it is 4 X2 X1 X 1

Ans 8/24 =1/3

[StaceyKoprince]

Thanks, stock, for the link to the prior discussion. Just a reminder to everyone: search first to see whether a problem has already been discussed. Then you don't have to wait for a reply! :)

john, follow that link and let us know if that doesn't answer your question.