If a cone, a hemisphere and a cylinder have equal bases and have same height, then the ratio of their volumes is

1. 1 : 3 : 2

2. 2 : 3 : 1

3. 2 : 1 : 3

4. 1 : 2 : 3

If a solid right circular cone of height 24 cm and base radius 6 cm is melted and recast in the shape of sphere, then the radius of the sphere is

1. 4 cm

2. 6 cm

3. 8 cm

4. 12 cm

If a solid circular cylinder of iron whose diameter is 15 cm and height 10 cm is melted and recasted into a sphere, then the radius of the sphere is

1. 15 cm

2. 10 cm

3. 7.5 cm

4. 5 cm