Question

The weight of $65$ books is $13kg.$
(i) What is the weight of $80$ such books?
(ii) How many such books weigh $6.4kg$?

Answer 1

Weight of $65$ books $=13kg$
(i) Weight of $1$ book $=\frac{13}{65}=\frac{1}{5}kg$

Weight of $80$ books $=80\times \frac{1}{5}=16kg$
(ii) Number of books weighing $13kg=65$
Number of books weighing $1kg=\frac{65}{13}=5$
Number of books weighing $6.4kg=6.4\times 5=32books$