$A$ cylindrical jar of diameter $24\, cm$ contains water to a height of $30\, cm$. $A$ spherical steel ball is dropped into the jar and the level of the water rises by $67.5\, mm$. The diameter of the ball is......$cm$.

$A$ hemisphere is placed on top of a cube. Its front view is shown in the given figure. The total height of the figure is $221 \ cm$. The ratio of the curved surface area of the hemisphere to the total surface area of the cube is $11:42$. What is the total volume (in $cm^3$) of the figure?

$A$ cone and a cylinder having the same area of the base have also the same area of curved surfaces. If the height of the cylinder is $2 \, m$,find the slant height of the cone (in $m$).

$A$ field is in the form of a rectangle of length $18\, m$ and width $15\, m$. $A$ pit,$7.5\, m$ long,$6\, m$ broad and $0.8\, m$ deep,is dug in a corner of the field and the earth taken out is evenly spread over the remaining area of the field. The level of the field raised is......$cm$

$3$ solid cubes whose edges are $6, 8$ and $10 \, cm$ respectively,are melted and formed into a single cube. If there is no loss of metal in the process,find the edge of the new cube (in $cm$).

The volumes of two cubes are in the ratio of $8: 125$. Find the ratio of their edges and surface areas.