Answer
$k=\dfrac{10}{3}$
When $k=-0.3$, $y=-1$.
Work Step by Step
Since $y$ varies directly as $x,$ then the model equation is $y=kx.$ Using the given values, $
y=\dfrac{2}{3} \text{ and }
x=0.2
,$ then
\begin{align*}
y&=kx
\\\\
\dfrac{2}{3}&=k\left(0.2\right)
\\\\
\dfrac{2}{3}&=0.2k
\\\\
\dfrac{2}{3}&=\dfrac{1}{5}k
&\text{ (express $0.2$ as a fraction)}
\\\\
5\left(\dfrac{2}{3}\right)&=\left(\dfrac{1}{5}k\right)5
\\\\
\dfrac{10}{3}&=k
\\\\
k&=\dfrac{10}{3}
\end{align*}
With the value of $k$ above, the variation equation is $y=
\dfrac{10}{3}
x.$ Substituting $x=-0.3$ in the derived variation equation, then the value of $y$ is
\begin{align*}
y&=\dfrac{10}{3}(-0.3)
\\\\
y&=\dfrac{10}{3}\left(-\dfrac{3}{10}\right)
&\text{ (express $-0.3$ as a fraction)}
\\\\
y&=-1
.\end{align*}
