What is the ruling on students studying summaries prepared by some teachers, from which exam questions are derived? Is this considered cheating and an injustice to other students? And what is the ruling on a teacher who assists students in cheating during an exam?

There is no harm in summarizing lessons and formulating them as questions, as this helps students and saves time and effort. This is not considered an injustice to others, as it is available to everyone and is not the only path to success. However, for the teacher to dictate the answers to the questions to students during an exam is clear and impermissible cheating.