Question

Question 8

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

Answer 1

The weight of 72 books = 9 kg

Applying unitary method, where firstly we find the value of one unit and then the value of required number of units.

$\therefore$ The weight of 1 book = $\frac{9kg}{72book}$ = $\frac{1}{8}$kg/book

$\therefore$ The weight of 40 books = $\frac{1}{8}\times 40$ kg = 5kg

Thus, the weight of 40 books is 5kg.