This article is from the Puzzles FAQ, by Chris Cole firstname.lastname@example.org and Matthew Daly email@example.com with numerous contributions by others.
What are some errors made in puzzle books?
Charles W. Trigg, Mathematical Quickies, Dover, 1985, #93
Angela Dunn, ed., Mathematical Bafflers, Dover, 1980, p. 112
David Wells, The Penguin Book of Curious and Interesting Puzzles, Penguin,
1992, #373 & #554