If the average marks of three classes of 55, 60, and 65 students are 55, 60, and 65 respectively, find the approximate average marks of all the students combined.

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.