how to calculate probability of winning exactly one number at lottery












0












$begingroup$


There are 38 numbers, I pick 7. What are probabilities I win exactly one number, no more and no less.



Is this possible to calculate.



It would be simple to calculate what are the chances I don't win any number, but how can you calculate chances of winning exactly one?










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$endgroup$












  • $begingroup$
    To be clear, are you saying that you choose 7 numbers between 1 and 38, and there are 7 winning numbers, and there is exactly one match? If so, are repetitions allowed i.e. can you choose (1,1,1,1,1,1,1)?
    $endgroup$
    – pwerth
    Jan 16 at 19:30










  • $begingroup$
    @pwerth: yes, 7 numbers between 1 and 38 and no repetions are allowed. If 16 is selected, it's eliminated.
    $endgroup$
    – Stenga
    Jan 16 at 19:32
















0












$begingroup$


There are 38 numbers, I pick 7. What are probabilities I win exactly one number, no more and no less.



Is this possible to calculate.



It would be simple to calculate what are the chances I don't win any number, but how can you calculate chances of winning exactly one?










share|cite|improve this question









$endgroup$












  • $begingroup$
    To be clear, are you saying that you choose 7 numbers between 1 and 38, and there are 7 winning numbers, and there is exactly one match? If so, are repetitions allowed i.e. can you choose (1,1,1,1,1,1,1)?
    $endgroup$
    – pwerth
    Jan 16 at 19:30










  • $begingroup$
    @pwerth: yes, 7 numbers between 1 and 38 and no repetions are allowed. If 16 is selected, it's eliminated.
    $endgroup$
    – Stenga
    Jan 16 at 19:32














0












0








0





$begingroup$


There are 38 numbers, I pick 7. What are probabilities I win exactly one number, no more and no less.



Is this possible to calculate.



It would be simple to calculate what are the chances I don't win any number, but how can you calculate chances of winning exactly one?










share|cite|improve this question









$endgroup$




There are 38 numbers, I pick 7. What are probabilities I win exactly one number, no more and no less.



Is this possible to calculate.



It would be simple to calculate what are the chances I don't win any number, but how can you calculate chances of winning exactly one?







probability






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 16 at 19:28









StengaStenga

276




276












  • $begingroup$
    To be clear, are you saying that you choose 7 numbers between 1 and 38, and there are 7 winning numbers, and there is exactly one match? If so, are repetitions allowed i.e. can you choose (1,1,1,1,1,1,1)?
    $endgroup$
    – pwerth
    Jan 16 at 19:30










  • $begingroup$
    @pwerth: yes, 7 numbers between 1 and 38 and no repetions are allowed. If 16 is selected, it's eliminated.
    $endgroup$
    – Stenga
    Jan 16 at 19:32


















  • $begingroup$
    To be clear, are you saying that you choose 7 numbers between 1 and 38, and there are 7 winning numbers, and there is exactly one match? If so, are repetitions allowed i.e. can you choose (1,1,1,1,1,1,1)?
    $endgroup$
    – pwerth
    Jan 16 at 19:30










  • $begingroup$
    @pwerth: yes, 7 numbers between 1 and 38 and no repetions are allowed. If 16 is selected, it's eliminated.
    $endgroup$
    – Stenga
    Jan 16 at 19:32
















$begingroup$
To be clear, are you saying that you choose 7 numbers between 1 and 38, and there are 7 winning numbers, and there is exactly one match? If so, are repetitions allowed i.e. can you choose (1,1,1,1,1,1,1)?
$endgroup$
– pwerth
Jan 16 at 19:30




$begingroup$
To be clear, are you saying that you choose 7 numbers between 1 and 38, and there are 7 winning numbers, and there is exactly one match? If so, are repetitions allowed i.e. can you choose (1,1,1,1,1,1,1)?
$endgroup$
– pwerth
Jan 16 at 19:30












$begingroup$
@pwerth: yes, 7 numbers between 1 and 38 and no repetions are allowed. If 16 is selected, it's eliminated.
$endgroup$
– Stenga
Jan 16 at 19:32




$begingroup$
@pwerth: yes, 7 numbers between 1 and 38 and no repetions are allowed. If 16 is selected, it's eliminated.
$endgroup$
– Stenga
Jan 16 at 19:32










1 Answer
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$begingroup$

You have chosen $7$ numbers. In order for you to match exactly one number, the winning numbers must include $6$ of the $31$ numbers you did not choose.
$$frac{7cdotbinom{31}{6}}{binom{38}{7}}approx40.839%$$






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    1 Answer
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    active

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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    2












    $begingroup$

    You have chosen $7$ numbers. In order for you to match exactly one number, the winning numbers must include $6$ of the $31$ numbers you did not choose.
    $$frac{7cdotbinom{31}{6}}{binom{38}{7}}approx40.839%$$






    share|cite|improve this answer









    $endgroup$


















      2












      $begingroup$

      You have chosen $7$ numbers. In order for you to match exactly one number, the winning numbers must include $6$ of the $31$ numbers you did not choose.
      $$frac{7cdotbinom{31}{6}}{binom{38}{7}}approx40.839%$$






      share|cite|improve this answer









      $endgroup$
















        2












        2








        2





        $begingroup$

        You have chosen $7$ numbers. In order for you to match exactly one number, the winning numbers must include $6$ of the $31$ numbers you did not choose.
        $$frac{7cdotbinom{31}{6}}{binom{38}{7}}approx40.839%$$






        share|cite|improve this answer









        $endgroup$



        You have chosen $7$ numbers. In order for you to match exactly one number, the winning numbers must include $6$ of the $31$ numbers you did not choose.
        $$frac{7cdotbinom{31}{6}}{binom{38}{7}}approx40.839%$$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 16 at 19:38









        Daniel MathiasDaniel Mathias

        1,29018




        1,29018






























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