How can you say " I don't know" in a mysterious way?

Your guess is as good as mine.

This idiom means: 

Definition From Dictionary: 

1-used to tell someone that you do not know any more about a subject than the person that you are talking to does. 2- something that you say when you do not know the answer to a question3- it used for telling someone that you know as little about something as they know

Example:

 'How long do you think this job will take?' 'Your guess is as good as mine.'

"What's he doing?" "Your guess is as good as mine."

“Who's going to win?” “Your guess is as good as mine.”

Quick Quiz:

Someone might say "your guess is as good as mine" if

they want you to guess something they're not sure about something they're sure about something sources : http://www.englishclub.com idioms.thefreedictionary.com www.englishclub.com

Raedah Alyousif