Good Riddles

Question: What is something that you always have with you but you always leave behind?

Question: What is 40 divided by 1/2, plus 15?

Question: If you toss a coin ten times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

Question: A trail, a union, together tied.
Come across me and you will find,
you cannot change the course I'm on,
without me you cannot travel on.

What am I?

Question: There were 3 men playing on a field playing a game. The guy that had the lowest score won the game. How is this possible?