The ratio between the curved surface area and the total surface area of a right circular cylinder is 3 : 5. Find the ratio between the height and the radius of the cylinder.

If radii of two circular cylinders are in the ratio 3 : 4 and their heights are in the ratio 6 : 5, find the ratio of their curved surface areas.

The length, the breadth and the height of a cuboid are doubled, the ratio between the volumes of the new cuboid and the original cuboid is :

1. 4 : 1

2. 1 : 4

3. 8 : 1

4. 1 : 8

The radius of a cylinder is doubled and its height is halved; then the new volume is :

1. same

2. 2 times

3. 4 times

4. 8 times