Normally, you can do the next question you must pass the current question. So you can complete one section you must answer the questions correctly on all questions in the section.
75% Pass Mark has the processed from user attempts to answer the question. Because of this course, you will never get failed the question. You have to try to answer the question until you answer correctly, you can go to the next question.
75%% Pass Mark is the number that you must pass in all questions. This means that 25% is the number that you can try to fail the questions.
Therefore, currently the course has 27 questions. It is means when you had attempted to answer the question and you got an incorrect answer 7 times (25% of 27 is 7). You failed the course.