Thursday

March 5, 2015

March 5, 2015

Posted by **sarah** on Saturday, July 6, 2013 at 1:25am.

- probability -
**MathMate**, Saturday, July 6, 2013 at 6:31amThis is a problem of conditional probability. The shortcut to the answer is consider only the outcomes where the first child is a girl, and calculate the probability among those where both are girls.

I.E.

Ω={GG,GB}

favourable outcome: {GG}

So assuming all outcomes are equally probable, then

P(GG|first child is a girl)=1/2

The proper way is to use the definition:

P(GG|GX) ...both girls given first child is a girl

=P(GG∩GX)/P(GX)

=P(GG)/P(GX) .. since P(GG&GX)=P(GG) by absorption

=(1/4)/(1/2)

=1/2

**Answer this Question**

**Related Questions**

Math - In a family with two children, what are the probabilities of the ...

odds of... - Does anyone know the odds of having Two girls as children as ...

math - Below is a sample space for a family with 3 children. BGG stands for the...

math - Assuming boy and girl babies are equally likely, find the probability ...

Help????????????????????/ - Assume a family is planning to have three children. ...

Math - In a family with two children, what are the probabilities of the ...

math - Below is a sample space for a family with 3 children. BGG stands for the ...

math - A couple intends to have four children. Assume that having a boy and girl...

math probablity - Assume a family is planning to have three children. A. What is...

Math-probablity - Assume a family is planning to have three children. A. What is...