In a sun and planet type gear, the annular gear (D) has 100 internal teeth, the sun gear (A) has 50 external teeth and a planet gear (B) has 25 external teeth. The gear (B) meshes with gear (D) and gear (A). The gear (B) is carried on the arm (E), which rotates about the centre of annular gear (D), if the gear (D) is fixed and arm rotates at 20 r.p.m., then determine the speeds of gears (A) and (B).