Most of the participants were told the problems they give his teacher. Some people never say He gave the reason that they want to solve the problem by itself, because it is his problem.
Most students have said those problems to his instructor. Some people never say They argue that they need to solve problems on their own because it is his problem.
Most of the students said issues them to his instructor. Some people never tell. He reasoned that they must solve the problem by yourself because it's his problem.