One of my kids had the same sort of quiz/test given, but he and his friend had a concern with it. When I read it, I was inclined to agree with them that it doesn't work the way the writer intends.

Presumably, each question contains an instruction to follow. Being instructed to read all questions first doesn't mean you then do what any of the other questions instruct. Why, after reading all other 99 questions first, do you do what question 100 instructs but not what the others instruct?