The cost of papering the four walls of a room 12 m long at ₹ 6.50 per square metre is ₹ 1,638 and the cost of matting the floor at ₹ 3.50 per square metre is ₹ 378. Find the height of the room.

The dimensions of a field are 15 m × 12 m. A pit 7.5 m × 6 m × 1.5 m is dug in one corner of the field and the earth removed from it, is evenly spread over the remaining area of the field. Calculate, by how much the level of the field is raised.

Three cubes, each of side 6 cm, are joined end to end. Find the surface area of resulting cuboid.

Find :

(i) the volume

(ii) the total surface area

(iii) the lateral surface area and

(iv) the length of the diagonal of a cube of side 10 cm.