I remember seeing advice regarding the SAT and AP exams that recommended guessing when eliminating either one or two responses. Almost nobody seemed to know the theory behind it, which I guess is why both options sounded perfectly plausible. I was horrified when my AP Lit teacher recommended to the class guessing only if 2 or more responses could be eliminated, and couldn't understand the math I did to show otherwise and wondered how such a thing was possible then there was a "penalty" for guessing (yes, she actually based her understanding of the situation on the name given rather than on doing any logical analysis; Orwell was surely rolling in his grave). Thankfully, she decided to trust me anyways.