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mathmath333

  • one year ago

If the first child of a couple is a boy.Find the probablity that the second child being a boy.

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  1. mathmath333
    • one year ago
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    \(\large \color{black}{\begin{align} & \normalsize \text{ If the first child of a couple is a boy.Find the }\hspace{.33em}\\~\\ & \normalsize \text{probablity that the second child being a boy.}\hspace{.33em}\\~\\ \end{align}}\)

  2. anonymous
    • one year ago
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    lol

  3. ParthKohli
    • one year ago
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    Depending on one's interpretation of probability, the answer is either 1/2 or 1/3.

  4. AlexandervonHumboldt2
    • one year ago
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    0? cause in a couple there is 1 girl and 1 boy if i remmeber correctly

  5. anonymous
    • one year ago
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    hahaha

  6. anonymous
    • one year ago
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    i think this type of question would not account for past results...

  7. anonymous
    • one year ago
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    unless your a baby predictor

  8. ParthKohli
    • one year ago
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    Read this: http://mathforum.org/dr.math/faq/faq.boygirl.choose.html

  9. ganeshie8
    • one year ago
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    similar problem : If you rolled a coin two times and if you saw HEAD first time, whats the probabiltiy that you see a HEAD on second roll too ?

  10. AlexandervonHumboldt2
    • one year ago
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    hahah gane, i'm bad at prob, but i would say 0

  11. ParthKohli
    • one year ago
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    @ganeshie8 What do you think the answer should be? 1/2?

  12. anonymous
    • one year ago
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    is that called mutually exclusive? i forgot

  13. mathmath333
    • one year ago
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    1/2

  14. AlexandervonHumboldt2
    • one year ago
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    it can be 1/2 as well

  15. anonymous
    • one year ago
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    what if you got con-joined twins one a female and the other a male

  16. anonymous
    • one year ago
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    if thats ever possible

  17. ganeshie8
    • one year ago
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    Yes, it has to be 1/2 if it is an unbiased coin; the coin has no memory, it wont remember the previous roll and decide itself to roll on a different face the next time

  18. mom.
    • one year ago
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    1/3 (;

  19. ParthKohli
    • one year ago
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    That's what I think too. However, this problem is a lot like the Monty Hall Problem, and given that one child is a boy, we eliminate the GG case, which leaves us with BG, GB, BB. That sounds like 1/3.

  20. ParthKohli
    • one year ago
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    But again, it should be 1/2.

  21. mathmath333
    • one year ago
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    It is from independent event problem

  22. AlexandervonHumboldt2
    • one year ago
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    hmm bg=gb it is not said that the order is needed i would say 1/2 or 0

  23. mom.
    • one year ago
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    female gametes-->XX male gametes --->XY when u fuse u get either ----> XX or XY so it will be 1/2

  24. ganeshie8
    • one year ago
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    The probability would be different only if the experiment had already taken place, I think. Then, we can use Bayee inference and use conditional probability..

  25. ganeshie8
    • one year ago
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    If the second coin is not rolled yet, then the probability of seeing HEAD on it is 1/2; this much is non negotiable.

  26. ganeshie8
    • one year ago
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    On the other hand, if you have rolled the coins and had the results already, then the sample space is : {HH, HT, TH, TT} the probability would be 1/3; but clearly, in the main question the baby was not born yet, so the probabiblity for our main question should be 1/2.

  27. ParthKohli
    • one year ago
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    Ohhh, so it's about an unborn baby.

  28. ParthKohli
    • one year ago
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    Then definitely 1/2.

  29. ganeshie8
    • one year ago
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    ** On the other hand, if you have rolled the coins and had the results already, then the sample space is : {HH, HT, TH, TT} If somebody tells you that one coin is H, the probability for other coin to be H would be 1/3; but clearly, in the main question the baby was not born yet, so the probabiblity for our main question should be 1/2.

  30. ParthKohli
    • one year ago
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    If we're differentiating between the elder and the younger child, then 1/2 is surely the answer.

  31. mom.
    • one year ago
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    (;

  32. AlexandervonHumboldt2
    • one year ago
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    \(\Huge\color{black}{☺☻☺☻☺☻☺☻☺☻}\)

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