There are 70 students in a class and their average marks in the annual examination is 35. If the average marks of the passed students is 60 and the average marks of the failed students is 25, find the number of failed students.

What is the average number of students in B.Tech (220), M.Tech (140), and B.A (4344) courses together?

A class has two sections A and B, which have 36 and 44 students respectively. If the average weight of section A is 40 kg and that of section B is 35 kg, find the average weight of the whole class.