A uniform metre rule of weight \(2.0\,\text{N}\) is pivoted at the \(40\,\text{cm}\) mark. A \(3.0\,\text{N}\) weight is hung at the \(10\,\text{cm}\) mark. At what position \(x\) (in cm) from the zero end must a \(4.0\,\text{N}\) weight be hung so that the rule is in equilibrium?