$A$ milk container of height $16 \, cm$ is made of metal sheet in the form of a frustum of a cone with radii of its lower and upper ends as $8 \, cm$ and $20 \, cm$ respectively. Find the cost of milk at the rate of $Rs. \, 22$ per $litre$ which the container can hold. (in $Rs.$)

The volume of a cylinder is $20 \pi \, cm^3$ and its height is $5 \, cm$. Then,the diameter of the cylinder is $\ldots \ldots \ldots \ldots \, cm$.

$A$ bucket is in the form of a frustum of a cone of height $30 \,cm$ with radii of its lower and upper ends as $10 \,cm$ and $20 \,cm$,respectively. Find the capacity and surface area of the bucket. Also,find the cost of milk which can completely fill the container,at the rate of $Rs. \, 25$ per $litre$ (use $\pi = 3.14$).

The volume of a cone is $9504\,cm^{3}$ and its radius is $18\,cm$. Then,its height is $\ldots\,cm$.

If two solid hemispheres of same base radius $r$ are joined together along their bases, then the curved surface area of this new solid is (in $\pi r^{2}$)

Volume of a cone $= \dots$