The marks obtained by a group of students in a short class test are grouped as follows:
Marks
0–5
5–10
10–15
15–20
20–25
Number of students
6
11
f
7
5
The modal mark of the distribution is 12.
(i) Find the missing frequency f.
(ii) Calculate the total number of students who took the test after inserting the value of f.
(iii) Comment, with one reason, on whether the class 10–15 continues to be the modal class after your calculation.