If $210\, m^{3}$ of sand is thrown into a tank $12\, m$ long and $5\, m$ wide,find how much the water level will rise? (in $m$)

$2\, cm$ of rain has fallen on a $1\, km^2$ of land. Assuming that $50\%$ of the raindrops could have been collected and contained in a pool having a $100\, m \times 10\, m$ base,by what level would the water level in the pool have increased? (in $m$)

If the volumes of two cubes are in the ratio $27: 1$,the ratio of their edges is

The perpendicular height of a conical tent is $4 \frac{2}{3} \text{ m}$ and the diameter of its base is $6 \text{ m}$. If $11$ persons can sleep in this tent,find how many average cubic meters $(m^3)$ of air each person gets?

If the radius of a cylinder is doubled and the height is halved,then what would be the ratio between the new curved surface area and the previous curved surface area of the cylinder?

$A$ hemisphere is made of lead. Its radius is $6 \, cm$. It is cast into a right circular cone of $75 \, cm$ height. The radius of the base of the cone is ......... $cm$.