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    There are two children in a family. If it is given that at least one of them is a boy, what is the probability that both the children are boys?
    Question

    There are two children in a family. If it is given that at least one of them is a boy, what is the probability that both the children are boys?

    A.

    34\frac{3}{4}

    B.

    23\frac{2}{3}

    C.

    13\frac{1}{3}

    D.

    14\frac{1}{4}

    Correct option is C

    Step 1: Total possible outcomes

    For two children, each child can either be a boy (B) or a girl (G). The total outcomes are:
    {BB,BG,GB,GG}\{BB, BG, GB, GG\}
    There are 4 total outcomes.

    Step 2: Favorable outcomes (at least one boy)
    If at least one of the children is a boy, we exclude the outcome GG . The remaining outcomes are:
    BB, BG, GB
    There are 3 favorable outcomes.

    Step 3: Probability formula
    The probability that both children are boys, given that at least one of them is a boy, is:
    P(both boys | at least one boy)=Favorable outcomes for both boysTotal favorable outcomesP(\text{both boys | at least one boy}) = \frac{\text{Favorable outcomes for both boys}}{\text{Total favorable outcomes}}

    Step 4: Calculate the probability
    The only outcome where both children are boys is BB . Thus, the number of favorable outcomes is 1 :
    P(both boys | at least one boy)=13P(\text{both boys | at least one boy}) = \frac{1}{3}

    Final Answer:

    The probability that both children are boys, given that at least one of them is a boy, is:
    13\frac{1}{3}

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