Question : If the radius of a sphere is decreased by 48%, then by what percentage does its surface area decrease?

Option 1: 82.91%

Option 2: 72.96%

Option 3: 78.98%

Option 4: 86.26%

Question : If the surface area of a sphere is 346.5 cm², then its radius is: (Take $\pi=\frac{22}{7}$)

Option 1: 7 cm

Option 2: 3.25 cm

Option 3: 5.25 cm

Option 4: 9 cm

Question : If the radius of a sphere is increased by 2.5 decimetres (dm), then its surface area increases by 110 dm$^2$. What is the volume (in dm$^3$ ) of the sphere?
(Take $\pi=\frac{22}{7}$)

Option 1: $\frac{13}{21}$

Option 2: $\frac{3}{7}$

Option 3: $\frac{4}{7}$

Option 4: $\frac{11}{21}$

Question : Water tax is increased by 20% but its consumption is decreased by 20%. Then, the increase or decrease in the expenditure of money is:

Option 1: 5% decrease

Option 2: 4% decrease

Option 3: No change

Option 4: 4% increase

Question : If the radius of a right circular cylinder open at both ends is decreased by 25% and the height of the cylinder is increased by 25%, the curved surface area of the cylinder thus formed:

Option 1: remains unaltered

Option 2: is increased by $25\%$

Option 3: is increased by $6.25\%$

Option 4: is decreased by $6.25\%$

Question : A solid metallic sphere of radius 4 cm is melted and recast into spheres of 2 cm each. What is the ratio of the surface area of the original sphere to the sum of the surface areas of the spheres, so formed?

Option 1: 2 : 1

Option 2: 2 : 3

Option 3: 1 : 2

Option 4: 1 : 4