The correct answers to all questions on a given taught subject in public schools is listed in an index in the back of the Teacher's Version of all textbooks.
The direction in which to teach the curriculum is spelled out in each chapter as well, along with the questions the teacher should ask and the direction to prod the students.
As I understand it the tests weren’t all alike. Therefore the teacher would have to know the answer without looking it up. And the reason the answers are there is so the teacher can answer the questions correctly. Even those who print the tests know a lot of the teachers are too dumb to pass the courses they teach.