$A$ hall is $15 \ m$ long and $12 \ m$ broad. If the sum of the areas of the floor and the ceiling is equal to the sum of the areas of the four walls,the volume of the hall is: (in $m^3$)

What is the volume (in $cm^{3}$) of a right pyramid of height $12\, cm$ and having a square base whose diagonal is $6\sqrt{2}\, cm$?

Consider the volumes of the following:
$1.$ $A$ parallelepiped of length $5\,cm$,breadth $3\,cm$ and height $4\,cm$.
$2.$ $A$ cube of each side $4\,cm$.
$3.$ $A$ cylinder of radius $3\,cm$ and length $3\,cm$.
$4.$ $A$ sphere of radius $3\,cm$.
The volumes of these in decreasing order are:

$A$ ball of lead,$4\, cm$ in diameter,is covered with gold. If the volume of the gold and lead are equal,then the thickness of gold is approximately (in $cm$).
$[$ Given $\sqrt[3]{2} = 1.259 ]$

$A$ right circular cylinder has a height of $18 \, cm$ and a radius of $7 \, cm$. The cylinder is cut into three equal parts by $2$ cuts parallel to the base. What is the percentage increase in the total surface area (in $\%$)?

The weight of a solid cube of iron of $1 \, cm$ edge is $17 \, gm$. What should be the weight of a similar cube of edge $3 \, cm$? (in $gm$)