$A$ 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 $\sqrt[3]{2} = 1.259 ]$

If the radius of a sphere is increased by $2 \, m$,its surface area is increased by $704 \, m^2$. What is the radius of the original sphere? (in $m$)
(use $\pi = \frac{22}{7}$)

$A$ rectangular water tank has dimensions $80\, m \times 40\, m$. Water flows into it through a pipe with an opening area of $40\, cm^{2}$ at a speed of $10\, km/hr$. By how much will the water level rise in the tank in half an hour (in $cm$)?

$A$ right cylinder and a right circular cone have the same radius and the same volume. The ratio of the height of the cylinder to that of the cone is

The circumference of one end of a frustum of a right circular cone is $48\, cm$ and of the other end is $34\, cm$. If the height of the frustum is $10\, cm$,its volume (in $cm^3$) is

$A$ large cube is formed from the material obtained by melting three smaller cubes of $3, 4$ and $5 \, cm$ side. What is the ratio of the total surface areas of the smaller cubes and the large cube?