$A$ reservoir, $30\, m$ long and $15\, m$ broad, is filled with water. How many gallons of water must be taken out to lower the level of water by $4\, m$? (in gallons)

$A$ hollow cylinder of height $3\,cm$ is recast into a solid cylinder. If the external and internal radii of the hollow cylinder are $4.3\,cm$ and $1.1\,cm$ respectively,what will be the radius of the solid cylinder? (in $cm$)

Water is flowing at the rate of $5 \text{ km/h}$ through a pipe of diameter $14 \text{ cm}$ into a rectangular tank which is $50 \text{ m}$ long and $44 \text{ m}$ wide. The time taken,in hours,for the rise in the level of water in the tank to be $7 \text{ cm}$ is:

The length of a room is $12\, m$,width $8\, m$,and height $6\, m$. How many boxes will it hold if each box occupies $1.5\, m^3$ of space?

$A$ right circular cone is $3.6 \ cm$ high and the radius of its base is $1.6 \ cm$. It is melted and recast into a right circular cone with a base radius of $1.2 \ cm$. The height of the new cone (in $cm$) is:

How many coins,$2 \, mm$ thick and $1.5 \, cm$ in diameter,should be melted in order to form a right circular cylinder with base diameter $6 \, cm$ and height $8 \, cm$?