The marks obtained by 55 students in a weekly Mathematics test are grouped as follows:
a. Class interval (marks): 10–20 20–30 30–40 40–50 50–60
Frequency: 6 9 14 18 8
(a) Class interval (marks): 10–20 20–30 30–40 40–50 50–60
Frequency: 6 9 14 18 8
(i) Identify the modal class.
(b) (ii) Find the mode of the marks scored by the students, correct to one decimal place.