Question

Weight of 12 mangoes is 2.4kg .What is the weight of 8 mangoes?

Answer 1

Hint: For this type of question first we should find the weight of one item given. Here the given item is mango, that is we should find the weight of one mango and then we should multiply that one mango weight with the required amount of mangoes.

Complete step-by-step answer:
The objective of the problem is to find the weight of 8 mangoes.
Given that the weight of twelve mangoes is 2.4kg.
First , we find the weight of one mango. We are finding the weight of one mango because it is easy to find the weight of eight mangoes. By multiplying one mango weight with eight mangoes we get eight mangoes.
Let the weight of one mango be x.

Number of mangoes	Weight of mangoes in kgs
12	2.4
1	x

To find x we use the cross multiplication. We get
 $12 \times x = 1 \times 2.4$
$ \Rightarrow 12x = 2.4 \\
   \Rightarrow x = \dfrac{{2.4}}{{12}} \\
$
Thus the weight of one mango is $\dfrac{{2.4}}{{12}}$kg.
But we have to find the weight of 8 mangoes. By multiplying the weight of one mango with eight mangoes we get the weight of eight mangoes .
Weight of eight mangoes $ = 8 \times \dfrac{{2.4}}{{12}}$
Multiplying numerator and denominator with 10 to take off the decimal point. We get
$ \Rightarrow 8 \times \dfrac{{2.4}}{{12}} \times \dfrac{{10}}{{10}}$
After multiplying numerator and denominator with 10 we get
$
   = 8 \times \dfrac{{24}}{{120}} \\
   = \dfrac{{24}}{{15}} = 1.6 \\
$
Thus , the weight of eight mangoes is 1.6kg.

Note: We use cross multiplication to compare the fractions . This method is useful when we are working with larger fractions for reducing them into smaller fractions, and to determine the value of a variable .