Your Guess Is As Good As Mine

The phrase ‘your guess is as good as mine’ is used when one doesn’t know the solution or answer to a problem instead of admitting “I don’t know or have the solution or answer.”

Example of use:  I asked my wife “how long will it take for the pie to bake?” and she answered, “your guess is as good as mine.”

Interesting fact

No-one knows the origin of this phrase. So your guess is as good as mine. Literally!