Answer
$y$ is also doubled
Work Step by Step
The variation model described by the problem is $
y=kx
.$
If $x=1,$ then
\begin{array}{l}\require{cancel}
y_1=k(1)
\\
y_1=k
.\end{array}
If $x=2$ ($x$ is doubled), then
\begin{array}{l}\require{cancel}
y_2=k(2)
\\
y_2=2k
.\end{array}
Comparing $y_1$ and $y_2$, when $x$ is doubled, then $y$ is also doubled.