Ask a silly question and you'll get a silly answer

Meaning

Literal meaning.

Origin

This sounds like a fairly recently coined proverb and, in it's precise wording, it is. Nevertheless, a mediaeval version with almost exactly the same sentiment written in Middle English predates the modern version by a good 500 years. William Caxton expressed the notion in his retelling of Aesop's Fables, 1484:

For to a folysshe demaunde behoueth a folysshe ansuere.

The modern translation had to wait until the 20th century, as in this example from the Florida newspaper The Ocala Star-Banner, December 1954:

He wished she'd give him a serious answer sometimes. Well, he thought, ask a silly question and you get a silly answer.