#### Answer

variation constant $=k=10$
equation of the variation: $y=10x$

#### Work Step by Step

$y$ varies directly as $x$ so the variation is direct.
The equation of a direct variation is of the form $y=kx$ where $k$ is the constant of variation.
To find the value of $k$ substitute the given values of $x$ and $y$ into $y=kx$ to obtain:
$$y=kx
\\2=k(\frac{1}{5})
\\5(2)=5(\frac{1}{5})
\\10=k$$
Thus, the equation of the variation is $y=10x$.