Question

Q. Weight of 15 identical books is 6kg.What is the weight of 45 such books?

Answer 1

$\frac{15}{45} = \frac{6}{x } \\ x = \frac{6 \times 45}{15} = 18kg$

Answer 2

6*45 = 270, multiply the weight of each book, and the amount you have which is 6 and 45 books equal 270 of weight