A rotating disc of 1.0m diameter has two eccentric masses of 0.5 kg each in radii of 50 mm and 60mm with an angular interval between them as 1500 on the plane of the disc. A balancing mass of 0.1 kg is to be attached in order to balance the disc. What should be the radial distance of the balancing mass from the eccentric mass which is at 50 mm radius?