The volume of a right circular cone, whose radius of the base is same as its altitude, and the volume of a sphere are equal. The ratio of the radius of the cone to the radius of the sphere is
Pipes A and B, when working together, can fill an empty tank in 8 hours. If B is stopped after 2 hours, it will take a total of 11 hrs to fill the tank. How long would it take A to fill the empty tank alone?