CUNY Math Challenge Blog

Solutions, Resources, Further Information & Discussion

Round 1: Problem 5

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A spherical ball with radius 1 is covered with ink and is placed in the hollow region between two concentric spheres with radii 3 and 5. The inked ball rolls about in this region, always touching the inside surface of the outer sphere and the outside surface of the inner sphere. Suppose that a region with area 1 on the outer sphere gets painted with ink by the rolling ball. Find the area of the region of the inner sphere that gets inked by the rolling ball.

Solution will be posted on March 16 at 12:00 a.m.

Written by Administrator

March 4, 2009 at 20:14

Posted in Round 1

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