Question : The radius of circle A is twice that of circle B and the radius of circle B is twice that of circle C. Their area will be in the ratio:

Option 1: 16 : 4 : 1

Option 2: 4 : 2 : 1

Option 3: 1 : 2 : 4

Option 4: 1 : 4 : 16

Question : The ratio of the total surface area and volume of a sphere is 2 : 7. Its radius is:

Option 1: 7.5 cm

Option 2: 10.5 cm

Option 3: 10 cm

Option 4: 7 cm

Question : A sphere and another solid hemisphere have the same surface area. The ratio of their volumes is:

Option 1: $2 \sqrt{3}: 8$

Option 2: $3 \sqrt{3}: 8$

Option 3: $3 \sqrt{3}: 4$

Option 4: $\sqrt{3}: 4$

Question : The ratio of the curved surface area of two cones is 1 : 4 and the ratio of slant height of the two cones is 2 : 1. What is the ratio of the radius of the two cones?

Option 1: 1 : 2

Option 2: 1 : 4

Option 3: 1 : 8

Option 4: 1 : 1

Question : If the radius of a sphere increases by 10%, what would be the change in the surface area of the sphere?

Option 1: 20%

Option 2: 21%

Option 3: 31%

Option 4: 25%