Probability that the second child is a girl?

Two parents have two children. One of the children (first or second) is a girl. What is the probability that the second child is a girl?

Answer:

There are 4 possibilities:

1. First boy, second boy.

2. First boy, second girl.

3. First girl, second boy.

4. First girl, second girl.

We know that one of the children is a girl, so the possibilities are 2, 3 and 4. Possibility one is excluded because both are boys. From those three , for 2 and 4 second child is a girl. It means that the probability is: 2/3.

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One Response to Probability that the second child is a girl?

  1. Petrea says:

    Funny thing you thinking about children :p

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