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  • Sep 1, 2010, 08:11 AM
    dembajang
    A newly married couple decides to continue having children until they have one of eac
    A newly married couple decides to continue having children until they have one of each sex. If the events of having a boy and a girl are independent and equiprobable, how many children should this couple expect?
  • Sep 1, 2010, 08:12 AM
    Curlyben
    Two, one of each ;)
  • Sep 1, 2010, 09:25 AM
    ebaines

    Three.

    The probability for exactly two children is 1/2 (i.e, the chance of the sex of child 2 being different from child 1). The probability of 3 children is (1/2)^2; the probabiliy of four is (1/2)^3 etc. So the expected value is:


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