A playground merry-go-round of radius r = 2.00 m has a moment of inertia = 250 ⋅ , and is rotating at 10.0 rev/min about a frictionless vertical axle. Facing the axle, a 20.0-kg child hops onto the merry-go-round, and manages to sit down on the edge. What is the new moment of inertia of the merry-go-round?