We are given the equation that represents a direct variation 2x - 4y = 0 .
We know direct variation equation y = k x.
Where x is the constant of variation.
In order to find if given equation is really a direct variation, we need to solve it for y.
2x - 4y = 0
Subtracting 2x from both sides, we get
-4y = -2x.
Dividing both sides by 4, we get
y = 1/2 x.
On comparing with direct variation equation y = k x. We can see that y = 1/2 x is also a direct variation equation.
And k = 1/2.
Therefore, correct option is A. Yes; k = 1/2.