The ratio of radii of $2$ right circular cylinders is $2:3$ and their heights are in the ratio $5:4$. The ratio of their curved surface area is

$A$ solid right circular cone of radius $4\, cm$ and height $7\, cm$ is placed inside a cylindrical vessel of radius $5\, cm$ and height $8\, cm$. How much water (in $cm^3$) will be required to fill the cylindrical vessel completely?

$3$ 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 ratio of total surface area to lateral surface area of a cylinder whose radius is $80 \text{ cm}$ and height $20 \text{ cm}$ is: (in $:1$)

$3$ cubes of metal whose edges are in the ratio $3: 4: 5$ are melted into a single cube,the length of whose diagonal is $48 \sqrt{3} \text{ m}$. Calculate the edges of the three cubes.

$A$ monument has $50$ cylindrical pillars each of diameter $50\, cm$ and height $4\, m.$ What will be the labour charges for cleaning these pillars at the rate of $50$ $paise$ per $m^{2}?$ (in $Rs.$) (Use $\pi=3.14$)