Question

A man whose weight is \[90kgs\] weighs \[15kg\] on the moon. What will be the weight of the man whose weight is \[60kg\]?

Answer 1

Hint: In order to find the weight of man whose weight is \[60kg\], we must consider the weight of the man whose weight is \[90kgs\]. We must consider that the given weights between the actual weight and the weight on the moon are in proportion. And then we must calculate the weight of the man on the moon who weighs \[60kg\].

Complete step by step answer:
Now let us have a brief regarding proportion. Proportion is nothing but saying that two ratios are equal. Two ratios can be written in proportion in the following ways- \[\dfrac{a}{b}=\dfrac{c}{d}\] or \[a:b=c:d\]. From the second way of notation, the values on the extreme end are called as extremes and the inner ones as means. Proportions are of two types: direct proportions and indirect or inverse proportions. In the direct proportion, there would be direct relation between the quantities. In the case of indirect proportion, there exists an indirect relation between the quantities.
Now let us find the weight of the man whose weight is \[60kg\].
Let us express the given statements in the form of proportion.
\[90:60::15:x\]
This can be expressed in ratios as-
\[\dfrac{90}{60}=\dfrac{15}{x}\]
Now let us find the unknown value \[x\], by the method of cross multiplication.
\[\begin{align}
  & \Rightarrow 90x=15\times 60 \\
 & \Rightarrow x=\dfrac{15\times 60}{90} \\
 & \Rightarrow x=10 \\
\end{align}\]
\[\therefore \] The man weighs \[10kgs\] when his actual weight is \[60kg\].

Note: We must always assign the variable to the value to be found. We can use ratios and proportions in our daily life. We can apply a ratio for adding the quantity of milk to water or water to milk. We can apply proportions for finding the height of the buildings and trees and many more.