A sphere and a cylinder have equal volumes. Find h in terms of r

Question

A sphere and a cylinder have equal volumes. The sphere has a radius 2r. The cylinder has radius r and height h. Find h in terms of r.

This came up in my maths paper today, anyone got any answers?

EDIT: Changed value of the radii so answers below are no longer correct

Answer 1

Volume of sphere is $V_s=\frac{4}{3}\pi(3r)^3=36\pi r^3$
Volume of cylinder is $V_c=\pi(2r)^2h=4\pi r^2h$

Hence, equating the volumes, we get $$36\pi r^3=4\pi r^2h \implies h=9r$$

Hopes this helps.