Logic Riddles

Question: You have 7 tennis balls that are all identical but one of them is slightly lighter than the others.

Using a balance scale and only two separate weightings, how can you find the light tennis ball?

Question: Travel a mile and I will change.
Travel a million and I will end as I started.

What am I?

Question: I'm number three.
But I'm not a number.
I'm hot and cold at the same moment but not at the same time.
I'm number three.
But I'm not a number.

Who or what am I?

Question: I was taking a plane to China and almost missed my flight. On my way to the terminal there were 7 other girls walking in the opposite direction. Each of these girls had 8 purses and each purse had 2 dogs.

How many in all were on the plane?

Question: A poor woman takes an expensive piece of jewelry, when she is caught the owner of the jewelry tells her "You can have this for seven figures or you will go to jail." The woman soon leaves with the jewelry.

How did she do this?