Question

The average weight of the students of a class is 60 kg. If eight new students of average weight 64 kg join the class, the average weight of the entire class becomes 62 kg. How many students were there in the class initially ?

Answer 1

Let there be n students in the class.

$60n+64\left(8\right)=62(n+8)$

$62n-60n=64\left(8\right)-62\left(8\right)$

$2n=16$

$n=8$

Therefore, initially there were 8 students in the class.