A cylindrical container of radius $6 \mathrm{cm}$ and height $15 \mathrm{cm}$ is filled with ice cream. The whole ice cream has to be distributed to $10$ children in equal cones with hemispherical tops. If the height of the conical portion is $4$ times the radius of its base, find the radius of the ice-cream cone in $\mathrm{cm}$.

A wooden article was made by scooping out a hemisphere from each end of a cylinder, as shown in the figure. If the height of the cylinder is $20 \mathrm{cm}$ and its base is of diameter $7 \mathrm{cm}$, find the total surface area of the article when it is ready.

If total surface area of the article is $k {\mathrm{cm}}^2$, then find $k$ ?

If the volume of the water left in the tub is $k {\mathrm{cm}}^3$, then find $k$ ?

If total surface area of the remaining solid is $k {\mathrm{cm}}^2$, then find $k$ ? 

If total surface area of the remaining solid is $k {\mathrm{cm}}^2$, then find $k$ ? (Use $\mathrm{\pi }=\frac{22}{7}$)

If volume of the remaining solid is $k {\mathrm{cm}}^3$, then find $k$ ?