$A$ container is in the form of a cylinder closed at one end by a hemisphere. The radius of the cylinder is $8.4 \,cm$ and the total height of the container is $52.8 \,cm$. How many litres of petrol can this container hold? (in $litres$)

$A$ factory manufactures $120000$ pencils daily. The pencils are cylindrical in shape,each of length $25 \,cm$ and circumference of base $1.5 \,cm$. Determine the cost of colouring the curved surfaces of the pencils manufactured in one day at $\operatorname{Rs.} 0.05$ per $dm^2$ (in $Rs.$).

$A$ solid metallic hemisphere of radius $8 \, cm$ is melted and recast into a right circular cone of base radius $6 \, cm$. Determine the height of the cone (in $cm$).

$A$ rocket is in the form of a right circular cylinder closed at the lower end and surmounted by a cone with the same radius as that of the cylinder. The diameter and height of the cylinder are $6 \, cm$ and $12 \, cm$,respectively. If the slant height of the conical portion is $5 \, cm$,find the total surface area and volume of the rocket. [Use $\pi = 3.14$]

$A$ metallic sphere with radius $6 \, cm$ is melted and recast into a wire of radius $0.4 \, cm$. Find the length of the wire in metres.

The volume of a cylinder is $550 \, cm^{3}$ and its radius is $5 \, cm$. Then,the height of the cylinder is $\ldots \ldots \ldots \, cm$.