Johnny's having trouble with his homework so he asks his dad "what's the difference between fact and theory?"
"That's easy" says his dad, "go ask your mother if she would have sex with a stranger for a million dollars and come back and tell me what she says".
"uh, ok" says Johnny, and he goes and asks his mother.
"For a million dollars? In a second!"
Johnny goes back and tells his dad her answer.
"Ok, now go and ask your sister the same thing".
He does, and she answers...
"Hell, I'd do it for 500 grand!"
Johnny goes and tells his dad her answer.
"Well, there you go" says his dad, "does that answer your question?"
"No!" yells Johnny,"that doesn't tell me a thing about the difference between fact and theory!"
"Sure it does" says his dad, "In theory we're sitting on 2 million dollars, but in fact we're just living with a couple of whores"