(b) A group of 441 students are required to take a test. Of these7 392 actually take the test, and 49 are absent that day. (1) 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. (ii) Of the 392 students who take the test, the numbers of students obtaining grades A, B7 C and D are in the ratio 5 : 12 : 8 : 3, respectively. Calculate the number of students obtaining each grade. Explain how you could check that your answers are plausible. [3] [4]