A group of 540 students are required to take a test. Of these, 495 actually take the test, and 45 are absent that day.
(i) Write down the ratio of the number of students who take the test
to the number of students who are absent. Simplify this ratio as far
as possible. [3]
(ii) Of the 495 students who take the test, the numbers of students
obtaining grades A, B, C and D are in the ratio 5 : 14 : 10 : 4,
respectively. Calculate the number of students obtaining each
grade. Explain how you could check that your answers are