Two classes M and N have average marks 25 and 40 respectively, the overall average obtained is 30. The ratio of the students in the class M and N is:

2 : 1 5 : 6 1 : 2 5 : 3

2 : 1

Let sum of marks of class M = 25m Sum of marks of class N = 40n According to question , \(\frac{25m + 40n }{m + n }\) = 30 25m + 40n = 30 m + 30n 5m = 10n Ratio of students in class M to class N = 2 : 1