Is this answer infinite solutions, one solution or no solution?

Determine the volume of a cylinder bucket if the diameter is 8.5 in. and the height is 11.5 in.

The volume of gas a balloon can hold varies directly as the cube of its radius. imagine a balloon with a radius of 3 inches can hold 81 cubic inches of gas. how many cubic inches of gas must be released to reduce the radius down to 2 inches?

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10