Answer
Find ${\bf n}\times{\bf v} $ (or ${\bf v}\times{\bf n} $).
Work Step by Step
The vector ${\bf n}\times{\bf v} $ is perpendicular to both ${\bf n}$ and ${\bf v}$.
One condition is obviously satisfied (perpendicular to ${\bf v}$).
Being perpendicular to a vector that is perpendicular to the plane,
the vector ${\bf n}\times{\bf v} $ lies in a plane parallel to our plane.
Thus, the second condition is also satisfied.
