$\"\"$

The values of $\"\"$ and $\"\"$ . \ \

Assume that, $\"\"$ is directly proportional to $\"\"$ .

$\"\"$

Thus, the variation model is in the form of $\"\"$ .

Now find the value of $\"\"$ .

Consider $\"\"$ .

Substitute the values of $\"\"$ and $\"\"$ in above equation.

$\"\"$

Divide each side by 5.

$\"\"$ .

Thus, the variation model is $\"\"$ . $\"\"$

The variation model is $\"\"$ .