The volumes of two spheres are in the ratio 64 : 27. The ratio of their surface areas is

1. 3 : 4

2. 4 : 3

3. 9 : 16

4. 16 : 9

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

A solid piece of iron in the form of a cuboid of dimensions 49 cm × 33 cm × 24 cm is molded to form a sphere. The radius of the sphere is

1. 21 cm

2. 23 cm

3. 25 cm

4. 19 cm

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