Answer
$y=\frac{1}{5} x$
Work Step by Step
$y$ varies directly with $x$, then $y=kx$ where $k$ is the constant of proportionality.
Since $y=2$ when $x=10$, then substituting these into the equation above gives:
$$2=k (10)\\
\frac{2}{10}=k\\
k=\frac{1}{5}$$
Therefore, the equation is y$=\frac{1}{5}x$ is the required general formula.