Attendance has never been a component of the grade for this course. However, over the years I have noticed that 40% of those who attend regularly receive an above average grade (B or better), while only 10% of those who do not attend regularly receive an above average grade. About 70% of the students attend class regularly. One student is randomly selected at the end of the semester. Find the probability that the student did not attend class regularly given that (s)he did not receive an above average grade