Question

The weight of 72 books is 9 kg. What is the weight of 40 such books?

Answer 1

The weight of 72 books = 9 kg
∴ The weight of 1 book =$\frac{9}{72}$
= $\frac{1}{8}$
∴ The weight of 40 books = $\frac{1}{8}\times40$
= 5 kg
Thus, the weight of 40 books is 5 kg.