Blapsing_Beard wrote:If you only see one girl in the house, then the chance that you are in house D is 0%, because it has 2 girls, and the other one you see is a boy?
It doesnt state you only see one child, who is a girl. It states that you only see one girl
Err, if you saw the other child, there would be no puzzle. Nice try at nit-picking, but you even managed to contradict yourself about "only". I didn't use the word at all.

Where I come from, houses have more than one room.
And people go out sometimes.
EDIT: You'd "love" 'Professor Layton and the Curious Village', which has puzzles full of annoying ambiguities.