Rowing to Shore and Then Running Away
is in a rowboat in the center of a circular lake (black dot). has to escape from (red dot), who knows must come ashore. Although can run faster than once on land, runs times faster than can row, where . Is there a strategy for to escape?
Richard F. Guy shows that can always escape when runs at most 4.6 times as fast as rows (solution 2).
 M. Gardner, The Colossal Book of Short Puzzles and Problems, New York: W. W. Norton, 2006 pp. 237, 256–257.