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ganeshie8

  • one year ago

Stacy prepared 20 different letters to be sent to 20 addresses. For each letter she prepared an envelope with its correct address. If the 20 letters to be put in to 20 envelopes at random, what is the probability that exactly 19 letters will be put in to the envelope with the correct address?

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  1. perl
    • one year ago
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    .

  2. ikram002p
    • one year ago
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    (1/20)^19 ?

  3. perl
    • one year ago
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    If 19 letters are in the correct envelopes, then the last letter must also be in the correct envelope. The probability of all 20 envelopes in the correct order is 1/20!

  4. ikram002p
    • one year ago
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    :O

  5. dan815
    • one year ago
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    yes i agree!

  6. dan815
    • one year ago
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    total possibilties - prob of 1 wrong, and prob of 0 wrong

  7. ganeshie8
    • one year ago
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    yeah that looks pretty neat, i guess then we can conclude the probability for exactly 19 letters putting in correct envelopes is 0 ?

  8. dan815
    • one year ago
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    oh wait lol everything is wring oops xD

  9. anonymous
    • one year ago
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    @dan815 Could you help with this math question

  10. dan815
    • one year ago
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    everything is right*

  11. ikram002p
    • one year ago
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    xD

  12. dan815
    • one year ago
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    the probabilitly is 0!

  13. perl
    • one year ago
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    oh its impossible :)

  14. dan815
    • one year ago
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    trying to trick us -.-

  15. dan815
    • one year ago
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    shame on this question

  16. ganeshie8
    • one year ago
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    guess i was partially successful :P

  17. dan815
    • one year ago
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    lol

  18. ikram002p
    • one year ago
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    -.-

  19. anonymous
    • one year ago
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    Hello

  20. perl
    • one year ago
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    What about 19 or above

  21. anonymous
    • one year ago
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    Could someone Help me http://openstudy.com/study#/updates/55912961e4b0428366270957

  22. perl
    • one year ago
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    At least 19 correct

  23. ikram002p
    • one year ago
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    im half a sleep anyway xD

  24. perl
    • one year ago
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    Then it would be 1/20!

  25. anonymous
    • one year ago
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    You guys are so mean Please Help :( Could someone Help me http://openstudy.com/study#/updates/55912961e4b0428366270957

  26. ganeshie8
    • one year ago
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    total permutations : 20! permutations in favor : 1 so yeah.. 1/20! on cursory thinking, this doesn't look like a binomial distribution, so other cases can get complicated hmm

  27. ikram002p
    • one year ago
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    try 10 to be correct ?

  28. Loser66
    • one year ago
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    Question: you have 20 envelopes and 20 letters; 19 are correct matching. Is it not that 20 are matching?? Since 19 right, how can the rest is wrong?

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