What you can do is split the force into vertical and horizontal components. The vertical component is 200sin(30) (down) and the horizontal component is 200cos(30) (left).
As with all moments, the sum of moments is the the sum of (Force x Perpendicular Distance), so the vertical force acts downwards and is 50mm from the pivot, and the horizontal force acts leftwards and is 150mm from the pivot.
The answer is 21 Nm.