The radii of two cylinders are in the ratio 2 : 3 and their heights are in the ratio 5 : 3. The ratio of their volumes is :

1. 4 : 9

2. 9 : 4

3. 20 : 27

4. 27 : 20

The ratio between the curved surface area and the total surface area of a right circular cylinder is 1 : 2. If the total surface area is 616 cm², the volume of the cylinder is :

1. 1232 cm³

2. 1078 cm³

3. 1848 cm³

4. 1548 cm³

The number of coins, 1.5 cm in diameter and 0.2 cm thick to be melted to form a right circular cylinder of height 10 cm and diameter 4.5 cm, is :

1. 380

2. 450

3. 472

4. 540