How many bricks are required to build a $15\, m$ long,$3\, m$ high,and $50\, cm$ thick wall,if each brick measures $25\, cm \times 12\, cm \times 6\, cm$?

How many small cubes,each of $96\,cm^{2}$ surface area,can be formed from the material obtained by melting a larger cube with $384\,cm^{2}$ surface area?

$A$ hollow sphere of internal and external diameters $4\,cm$ and $8\,cm$ respectively is melted into a cone of base diameter $8\,cm$. The height of the cone is......$cm$.

$A$ tank, $16 \, m$ long and $23 \, m$ wide contains water. How many cubic $m$ of water must be added to it to make the surface rise by $16 \frac{2}{3} \, cm$? (in $m^3$)

Water is flowing at the rate of $3 \, km/h$ through a circular pipe of $20 \, cm$ internal diameter into a circular cistern of diameter $10 \, m$ and depth $2 \, m$. In how much time will the cistern be filled?

$A$ spherical aquarium can accommodate $11$ fishes,and each fish requires $1.54 \, m^3$ of water. What is the volume of the aquarium? (in $m^3$)