Disc A having a mass of 2.0 kg and a radius of 40 cm, rotate clock-wise around a frictionless vertical axle at 30 rev/s. Disc B, as well 2.0 kg however having a radius of 20 cm, rotates counter-clockwise around that similar axle, although at a greater height than Disc A, at 30 rev/s. Disc B slides down the axle till it lands on top of Disc A, after which they rotate altogether. After the collusion, determine their common angular speed (in rev/s) and in which direction do they rotate?