Question

A man filled his car tank with 20 litres of diesel to travel exactly 480 km. At the end of the day, he finds 8 litres of diesel left in the tank. How much distance did he cover?

Answer 1

Given,
20 litres of diesel is required to cover 480 km.

At the end of the day, 8 litres of diesel is left.
So, litres of diesel consumed
= (20 - 8) = 12 litres

We know that, if, the number of litres of diesel consumed increases, then the distance covered also increases.

$\text{So, Litres of diesel}\left(x\right)\propto \text{Distance}\left(y\right)$
$\therefore \frac{x_1}{y_1}=\frac{x_2}{y_2}$

Given,
$x_1=20l$
$y_1=480km$
$x_2=12l$
$\text{and}{y}_2=\text{distance covered}$
$\Rightarrow y_2=\frac{x_2\times y_1}{x_1}$
$\Rightarrow y_2=\frac{12\times 480}{20}=288km$