ANSWER
[tex]yes \: \: k = \frac{1}{3} \: \: \: y = \frac{1}{3} x[/tex]
EXPLANATION
The given line passes through the origin, hence it has equation of the form,
[tex]y = kx[/tex]
Therefore y varies directly as x.
The line passes through the point (3,1)
This implies that,
[tex]1= k(3)[/tex]
[tex]k= \frac{1}{3} [/tex]
Hence the constant of variation is
[tex] \frac{1}{3} [/tex]
The equation is
[tex]y = \frac{1}{3} x[/tex]
