I absolutely hate hate when teachers do that. Usually its teachers who dont care, they just randomly pick some questions from the internet not even reading them, and then expects us to them, despite them being off spec and etc. But TBH now that your in yr 13, really who cares? You know what you need to do, just revise and do well in the end, these little test don't really matter at all. Unless of course its going to determining your predicted grades.
I would recommend no point learning answers which you would have never understood, cause no ones going to understand them, and this will seem fishy if your the only one getting it right. But do look at the answers which you know how to do, so if the teachers asks you how you got you know exactly how. Hope this helps, but I feel you!