Probability that friends meet.












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$begingroup$


Two friends decide to meet between 1PM and 2PM on a given day. There is a condition that whoever arrives first will not wait for the other for more than 15 minutes. What is the probability that they meet ?



How to solve this problem using Random Variables mathematically ?










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  • $begingroup$
    you need to figure out some boundary conditions - if A arrives at 1, then B has to arrive between 1 and 1:15, but if A arrives as 1:15 then B can arrive from 1:00 to 1:30 - the next boundary condition is at 1:45. You have to come up with a probability function, then integrate it
    $endgroup$
    – Cato
    Jan 26 '17 at 17:49










  • $begingroup$
    related math.stackexchange.com/questions/103015/…
    $endgroup$
    – Henry
    May 7 '17 at 18:55
















2












$begingroup$


Two friends decide to meet between 1PM and 2PM on a given day. There is a condition that whoever arrives first will not wait for the other for more than 15 minutes. What is the probability that they meet ?



How to solve this problem using Random Variables mathematically ?










share|cite|improve this question









$endgroup$












  • $begingroup$
    you need to figure out some boundary conditions - if A arrives at 1, then B has to arrive between 1 and 1:15, but if A arrives as 1:15 then B can arrive from 1:00 to 1:30 - the next boundary condition is at 1:45. You have to come up with a probability function, then integrate it
    $endgroup$
    – Cato
    Jan 26 '17 at 17:49










  • $begingroup$
    related math.stackexchange.com/questions/103015/…
    $endgroup$
    – Henry
    May 7 '17 at 18:55














2












2








2


1



$begingroup$


Two friends decide to meet between 1PM and 2PM on a given day. There is a condition that whoever arrives first will not wait for the other for more than 15 minutes. What is the probability that they meet ?



How to solve this problem using Random Variables mathematically ?










share|cite|improve this question









$endgroup$




Two friends decide to meet between 1PM and 2PM on a given day. There is a condition that whoever arrives first will not wait for the other for more than 15 minutes. What is the probability that they meet ?



How to solve this problem using Random Variables mathematically ?







probability probability-distributions






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asked Jan 26 '17 at 17:42









S PaulS Paul

10811




10811












  • $begingroup$
    you need to figure out some boundary conditions - if A arrives at 1, then B has to arrive between 1 and 1:15, but if A arrives as 1:15 then B can arrive from 1:00 to 1:30 - the next boundary condition is at 1:45. You have to come up with a probability function, then integrate it
    $endgroup$
    – Cato
    Jan 26 '17 at 17:49










  • $begingroup$
    related math.stackexchange.com/questions/103015/…
    $endgroup$
    – Henry
    May 7 '17 at 18:55


















  • $begingroup$
    you need to figure out some boundary conditions - if A arrives at 1, then B has to arrive between 1 and 1:15, but if A arrives as 1:15 then B can arrive from 1:00 to 1:30 - the next boundary condition is at 1:45. You have to come up with a probability function, then integrate it
    $endgroup$
    – Cato
    Jan 26 '17 at 17:49










  • $begingroup$
    related math.stackexchange.com/questions/103015/…
    $endgroup$
    – Henry
    May 7 '17 at 18:55
















$begingroup$
you need to figure out some boundary conditions - if A arrives at 1, then B has to arrive between 1 and 1:15, but if A arrives as 1:15 then B can arrive from 1:00 to 1:30 - the next boundary condition is at 1:45. You have to come up with a probability function, then integrate it
$endgroup$
– Cato
Jan 26 '17 at 17:49




$begingroup$
you need to figure out some boundary conditions - if A arrives at 1, then B has to arrive between 1 and 1:15, but if A arrives as 1:15 then B can arrive from 1:00 to 1:30 - the next boundary condition is at 1:45. You have to come up with a probability function, then integrate it
$endgroup$
– Cato
Jan 26 '17 at 17:49












$begingroup$
related math.stackexchange.com/questions/103015/…
$endgroup$
– Henry
May 7 '17 at 18:55




$begingroup$
related math.stackexchange.com/questions/103015/…
$endgroup$
– Henry
May 7 '17 at 18:55










1 Answer
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$begingroup$

One man must arrive before the other. The probability that man 1 arrives during the first $frac34$ hour is $frac34$. He'll then wait $frac14$ hour.



The probability that he arrives during the last $frac14$ hour is $frac14$, and then (on average he'll wait) $frac18$ hour.



So altogether the man 1 will wait $frac34 × frac14 + frac14 × frac18 = frac7{32}$.



So the probability that man 2 arrives while the man 1 is waiting is $frac7{32}$. Similarly if man 2 arrives before man 1. SO altogether, the probability of them meeting is $frac7{32} + frac7{32} = frac7{16}$






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    1 Answer
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    1 Answer
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    $begingroup$

    One man must arrive before the other. The probability that man 1 arrives during the first $frac34$ hour is $frac34$. He'll then wait $frac14$ hour.



    The probability that he arrives during the last $frac14$ hour is $frac14$, and then (on average he'll wait) $frac18$ hour.



    So altogether the man 1 will wait $frac34 × frac14 + frac14 × frac18 = frac7{32}$.



    So the probability that man 2 arrives while the man 1 is waiting is $frac7{32}$. Similarly if man 2 arrives before man 1. SO altogether, the probability of them meeting is $frac7{32} + frac7{32} = frac7{16}$






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      One man must arrive before the other. The probability that man 1 arrives during the first $frac34$ hour is $frac34$. He'll then wait $frac14$ hour.



      The probability that he arrives during the last $frac14$ hour is $frac14$, and then (on average he'll wait) $frac18$ hour.



      So altogether the man 1 will wait $frac34 × frac14 + frac14 × frac18 = frac7{32}$.



      So the probability that man 2 arrives while the man 1 is waiting is $frac7{32}$. Similarly if man 2 arrives before man 1. SO altogether, the probability of them meeting is $frac7{32} + frac7{32} = frac7{16}$






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        One man must arrive before the other. The probability that man 1 arrives during the first $frac34$ hour is $frac34$. He'll then wait $frac14$ hour.



        The probability that he arrives during the last $frac14$ hour is $frac14$, and then (on average he'll wait) $frac18$ hour.



        So altogether the man 1 will wait $frac34 × frac14 + frac14 × frac18 = frac7{32}$.



        So the probability that man 2 arrives while the man 1 is waiting is $frac7{32}$. Similarly if man 2 arrives before man 1. SO altogether, the probability of them meeting is $frac7{32} + frac7{32} = frac7{16}$






        share|cite|improve this answer









        $endgroup$



        One man must arrive before the other. The probability that man 1 arrives during the first $frac34$ hour is $frac34$. He'll then wait $frac14$ hour.



        The probability that he arrives during the last $frac14$ hour is $frac14$, and then (on average he'll wait) $frac18$ hour.



        So altogether the man 1 will wait $frac34 × frac14 + frac14 × frac18 = frac7{32}$.



        So the probability that man 2 arrives while the man 1 is waiting is $frac7{32}$. Similarly if man 2 arrives before man 1. SO altogether, the probability of them meeting is $frac7{32} + frac7{32} = frac7{16}$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 26 '17 at 18:10









        Kanwaljit SinghKanwaljit Singh

        8,5351517




        8,5351517






























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