The $CSA$ (Curved Surface Area) of a hemisphere is equal to $\ldots \ldots \ldots$

$A$ cylinder with radius $8 \, cm$ and height $9 \, cm$ is surmounted by a cone of height $15 \, cm$. Find the total surface area and the volume of the combined solid.

$A$ solid metallic sphere of radius $10.5 \, cm$ is melted and recast into a number of smaller cones,each of radius $3.5 \, cm$ and height $3 \, cm$. Find the number of cones so formed.

The volume of a sphere is equal to $\ldots \ldots \ldots . .$

$A$ rectangular water tank of base $11 \,m \times 6 \,m$ contains water up to a height of $5 \,m$. If the water in the tank is transferred to a cylindrical tank of radius $3.5 \,m$,find the height of the water level in the tank. (in $m$)

For a bucket in the shape of a frustum of a cone,the radii are $28\,cm$ and $7\,cm$ and the height is $45\,cm$. How many litres of water can it hold?