The ratio of the radius of sphere and hemisphere is 2 : 3. The difference between the curved surface area of hemisphere and sphere is 308 sq. cm. The radius of the sphere is equal to the radius of a right circular cylinder. The curved surface area of the cylinder is 880 sq. cm. Find the ratio between the height of cylinder and radius of hemisphere.
1
9 : 10
2
21 : 11
3
10 : 21
4
21 : 10
5
24 : 9