Since lines PS and QR are parallel, then the coefficient of x are the same when the line is equated in the form y = mx + c, where m is the gradient
So, for line QR, the gradient is 1/2
For PS, the equation is
3y = kx + 12
(divide both sides by 3)
y = (k/3)x + 4
Since the gradients are equal, k/3 = 1/2
(multiply both sides by 3)
k = 3/2
