Question

There are three houses next to one another and two kids live in each house. one house has two girls, and one house has a boy and a girl. If you were to walk into a house at random and see a girl, what is the probability that the other kid in the house is also a girl? And the answer is not 1/2.

Answer 1

Answer:

1/9

Step-by-step explanation:

There could be

1. Boy and a boy

2. Boy and a girl

3. Girl and a girl

Only one out of the three could have two girls: the last one. Meaning there is a 1/3 chance of walking into that one and a 1/3 chance that that house would have 2 girls. So it would be a 1/9 chance.

Hope this helps! :)

Answer 2

Answer:

4/9 of the time the other child is a girl.

Step-by-step explanation:

The trick is what's in the third house. There are 3 choices

b   g

b   b

g  g

So writing all three houses together we have

g   g           g    g             b  g

b   g           b    g             b b

                                       g  g

The first two houses are identical

1/3 * 1/2                for house 1

1/3 * 1/2                for house 2

1/3 * 1/3                for house 3

Now to explain it about. The probability of choosing 1 of the houses is 1/3 for all of the houses. The second number is the probability of getting 2 girls.

So the total probability is

1/6 + 1/6 + 1/9

2/6 + 1/9 = 6/18  + 2/18 = 8 / 18 = 4/9