Answer
$y=35$
Work Step by Step
Recall:
If $y$ varies directly as $x$ then, $y=kx$ where $k$ is the constant of variation.
Since $x=10$ when $y=7$, then:
\begin{align*}
y&=kx\\\\
7&=k(10)\\\\
\frac{7}{10}&=\frac{k(10)}{10}\\\\
\frac{7}{10}&=k
\end{align*}
Thus, the direct variation's equation is:
$$y=\frac{7}{10}x$$
To find the value of $y$ when $x=50$, substitute these values into the equation above to obtain:
\begin{align*}
y&=\frac{7}{10}x\\\\
y&=\frac{7}{10}(50)\\\\
y&=7(5)\\\\
y&=35
\end{align*}