This was in the Globe a few weeks ago. See if you can figure it out.
Bob is in a bar, looking at Susan, who is looking at Pablo. Bob is married. Pablo is not. Is a married person looking at an unmarried person?
c) Cannot be determined
Apparently 80% of people choose the wrong answer because we are "cognitive misers" where we put as little mental effort into solving a problem as possible.
I got it wrong. Boo. But I blame it on a hangover.