Logic Riddles

Question: A man has 3 children and half of them are girls, how is this possible?

Question: There are 31 horses on a cliff, first they jump into the air, then they come down and stop, then they stand still.

Why do they do this?

Question: You're stuck in a room with no way out, no windows, no doors, and no roof. All you've got is an apple and a knife. How do you get out?

Question: In Michigan you cannot take a picture of a man in a green hat.

Why?

Question: What`s in the middle of Paris?