$A$ top is made by joining a hemisphere to the base of a cone. The radius and the height of the conical part are $2.8 \, cm$ and $6.4 \, cm$ respectively. Find the volume of the top in $cm^3$.

$A$ 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 $Rs.$)

Water flows through a cylindrical pipe,whose inner radius is $1 \,cm$,at the rate of $80 \,cm/sec$ into an empty cylindrical tank,the radius of whose base is $40 \,cm$. What is the rise of water level in the tank in half an hour? (in $cm$)

$A$ cubical ice cream brick of edge $22 \, cm$ is to be distributed among some children by filling ice cream cones of radius $2 \, cm$ and height $7 \, cm$ up to its brim. How many children will get the ice cream cones?

Write 'True' or 'False' and justify your answer:
Two identical solid hemispheres of equal base radius $r \text{ cm}$ are joined together along their bases. The total surface area of the resulting solid is $6 \pi r^{2}$.

The radii of two $10 \, cm$ high metallic cylinders are $3.5 \, cm$ and $7 \, cm$. These cylinders are melted and recast to produce a cylinder with height $50 \, cm$. Find the radius of this new cylinder (in $cm$).