In answer to your Mechanics question posted in OC:
The clockwise and anti-clockwise moments have to be equal, the moment being equal to Wa, where W = weight and a = distance from pivot. Anti-clockwise motion is equal to 200 Nm, clockwise motion is equal to (150 + 10(3+x)) Nm = (180 + 3x) Nm. Therefore, 20m = 3x, and therefore x is equal to 20/3 m, or 6.666... m. :)