A tank 30 m long, 24 m wide and 4.5 m deep is to be made. It is open from the top. Find the cost of iron sheet required, at the rate of ₹ 65 per m², to make the tank.

The edges of three solid cubes are 6 cm, 8 cm and 10 cm. These cubes are melted and recasted into a single cube. Find the edge of the resulting cube.

The length, breadth and height of a cuboid (rectangular solid) are 4 : 3 : 2.

(i) If its surface area is 2548 cm², find its volume.

(ii) If its volume is 3000 m³, find its surface area.

The curved surface area of a cylinder, with length 10 cm and radius 7 cm, is :

1. 22 cm²

2. 308 cm²

3. 44 cm²

4. 440 cm²