Calculate the Density and Radius of the Ball Bearing

A graduated cylinder is filled to the 40.00mL mark
with a mineral oil.  The masses of the
cylinder before and after the addition of the mineral oil are 124.966 g and
159.446 g, respectively.  In a separate
experiment, a metal ball bearing of mass 18.713 g is placed in the cylinder and
the cylinder is again filled to the 40.00 mL mark with mineral oil.  The combined mass of the ball bearing and
mineral oil is 50.952 g.  Calculate the density and radius of the ball bearing.  (The volume of a sphere of radius r is (4/3)pr3.)