In a cylinder,if the radius is doubled and the height is halved,the curved surface area will be:

The dimensions of a cuboidal box are in the ratio $6: 4: 3$. The difference between the cost of covering it with white paper at the rate of $₹ 2.00$ per $m^2$ and with coloured paper at the rate of $₹ 2.50$ per $m^2$ is $₹ 1350$. Find the dimensions of the box.

The radius and slant height of a cone are $10 \, cm$ and $25 \, cm$ respectively. Find the total surface area of a cone. (in $cm^2$)

Find the curved surface area and the total surface area of a hemisphere with a radius of $17.5 \, cm$.

Write True or False and justify your answer in each of the following: If a sphere is inscribed in a cube,then the ratio of the volume of the cube to the volume of the sphere will be $6: \pi$.

$A$ cylindrical container of radius $14\, cm$ is partially filled with water. $A$ solid cuboid of iron with dimensions $22\, cm \times 16\, cm \times 7\, cm$ is submerged in it. Find the rise in the level of the water when the solid is completely submerged. (in $cm$)