Ineed an answer of the students in a math course, which was 92% of the students registered in the course, earned a passing grade for the course. find the number of students registered for the math course.

There is a problem with this question.
if 15 students is 92% of the class, the total class size is therefore
N=15*(100/92) = 16.3, or 16 students (to the nearest integer).

So far so good.

However, if we check back, 15 students out of 16 is 15/16*100%=93.75%, nowhere near 92%.  I have no idea where the 92% came from, and hence I doubt if there might not be a typo, by the submitting user, or the teacher.