The average weight of a class is 40 kg. If a student with a weight of 60 kg joins the class, the new average weight becomes 42 kg. Now, the total number of student in the class is
1
9
2
10
3
11
4
12
The average weight of a class is 40 kg. If a student with a weight of 60 kg joins the class, the new average weight becomes 42 kg. Now, the total number of student in the class is