The distribution below shows the scores obtained by students in an aptitude test.
Score
30–40
40–50
50–60
60–70
70–80
80–90
Number of students
7
x
25
y
11
5
It is given that:
1. The modal score of the distribution is 56.
2. The frequency of the class 60–70 exceeds that of the class 40–50 by 5, that is, y = x + 5.
a. (i) Determine the values of x and y.
b. (ii) Calculate the total number of students who appeared for the test.
c. (iii) State the modal class after inserting the calculated frequencies.