I don't know what you mean here. First there should be a verb in the first clause. If you meant the volume of the cylinder is "equal to n times the volume of the sphere", that's impossible. The volume of a cylinder inscribed in a sphere must be less than then volume of the sphere, not "n times the volume".
how to solve this??
i know using the pyth theorem , the square of radius of cylinder + 1/2 square of the height of the cylinder is equal to square of the sphere's radius
i also list two volume equations
but how to do the next step???
because there are two variable, it seems cannot be reduced to only 1 variables