$A$ cone of height $24\, cm$ and radius of base $6\, cm$ is made up of modelling clay. $A$ child reshapes it in the form of a sphere. Find the radius of the sphere (in $cm$).

$A$ copper rod of diameter $1 \,cm$ and length $8 \,cm$ is drawn into a wire of length $18 \,m$ of uniform thickness. Find the thickness of the wire. (in $mm$)

$A$ metallic sphere of radius $4.2 \, cm$ is melted and recast into the shape of a cylinder of radius $6 \, cm$. Find the height of the cylinder. (in $cm$) [Take $\pi = \frac{22}{7}$]

$A$ cubical block of side $7 \, cm$ is surmounted by a hemisphere. What is the greatest diameter the hemisphere can have? Find the surface area of the solid (in $cm^2$). [Use $\pi = \frac{22}{7}$]

$A$ copper wire,$3 \,mm$ in diameter,is wound about a cylinder whose length is $12 \,cm$ and diameter $10 \,cm$,so as to cover the curved surface of the cylinder. Find the mass of the wire,assuming the density of copper to be $8.88 \,g/cm^3$. (in $g$)

$A$ tent is in the shape of a cylinder surmounted by a conical top. If the height and diameter of the cylindrical part are $2.1 \, m$ and $4 \, m$ respectively,and the slant height of the top is $2.8 \, m$,find the area of the canvas used for making the tent. Also,find the cost of the canvas of the tent at the rate of $Rs. \, 500$ per $m^2$. (in $Rs.$) [Use $\pi = \frac{22}{7}$] (Note that the base of the tent will not be covered with canvas.)