Good Riddles

Question: Paul is 20 years old in 1980, but only 15 years old in 1985.How is this possible?

Question: What has a foot but no leg?

Question: A woman goes into a bank in Chicago and asks for a $1,000 loan for an upcoming trip she has planned to Asia. The loan officer tells her she will need collateral if she wants the loan.

She tells the loan officer "I'll leave my car, it's worth $150,000." The bank takes the car for the loan, laughing at her for leaving such expensive collateral.

A month later when the woman comes back she pays off her loan plus interest, costing her $1,020. The bank manager smirks at her and asks "While you were gone we found out you're very wealthy. Why would you get such a small loan and leave such expensive collateral?"

She tells him why and he realizes she's not as dumb as they thought. Why did she get the loan?

Question: One falls but never breaks and the other breaks but never falls?

What are they?

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?