Good Riddles

Question: It smells like blue paint,
pours like green paint,
and it looks like a red truck.

What is it?

Question:

Take me for a spin and I'll make you cool,
but use me when it's cool and you're a fool.

What am I?

Question: When is 1500 plus 20 and 1600 minus 40 the same thing?

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: A man finds a small iron coin dated 154 B.C., what's it worth?