Calculate the mode for the following data:
Marks
1 - 10
11 - 20
21 30
31 - 40
41 -50
51 - 60
61 - 70
No. of student
6
5
8
15
7
3
Draw a frequency polygon for the following frequency distribution: Class interval1−1011−2021−3031−4041−5051−60Frequency8361227