A dedicated sports-car enthusiast polishes the inside and outside surfaces of a hubcap that is a section of a sphere. When she looks into one side of the hubcap, she sees an image of her face 30 cm in back of the hubcap. She then flips the hubcap over and sees another image of her face 10 cm in back of the hubcap. How far is her face from the hubcap? What is the radius of the curvature of the hubcap?