Question

The weight of 72 books is 9 kg. (i) What is the weight of 80 such books? ​

Answer 1

Answer:

Let's use the concept of the unitary method.

From the given data,

Weight of 72 books = 9 kg

Hence, the weight of 1 book = $\frac{9}{72} = \frac{1}{8} \: kg$

Therefore, the weight of 40 books =

$( \frac{1}{8} ) \times 40 = 5 \: kg$

Thus, the weight of 40 books is 5 kg.

Answer 2

$\fcolorbox{green}{green}{Verified }$

Explanation:

The weight of 72 books is 9 kg

$The \: weight \: of \: 1 book \: = \bold{\frac{9}{72} kg}$

so,

The weight of 80book =

• $\longrightarrow \: \cancel{\frac{\cancel{9}}{72} \times \cancel{80}}$
• $\longrightarrow \: 10kg$

Hence, the weight of 80 such books is 10kg