A group of mathematics students in a school took an examination. Their scores (as a percentage) were summarized on a cumulative frequency diagram given below. 120- 110- 100- 90 80 70- 60 Cumulative Frequency 50 40 30 20- 10- 10 20 30 40 50 60 70 80 90 100 Examination Score a). How many students took the exam? b). Estimate the median exam score. c). The bottom 25% will need to take the exam over. From what score, and below, will require students to retake the exam? d). Those students with a score of 80 and above will move on to take another exam, how many students qualify for the next exam