A group of students has an average weight of 44 kg. One student weighing 40 kg leaves the group and another student weighing 34 kg joins. If the new average weight becomes 43.4 kg, how many students are there in the group?

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.