101 Puzzles in Thought and Logic

Do you like puzzles based on logic and reasoning? Try this one: In a certain bank the position of cashier, manager, and teller are held by Brown, Jones, and Smith, though not necessarily in that order. The teller, who was an only child, earns the least. Smith, who married Brown's sister, earns more than the manager. What position does each man fill?If you like to entertain yourself and stretch mental muscles on problems like this or more difficult ones, here are 101 entirely new problems for which you need no special knowledge, no mathematical training--simply the ability to reason clearly.Follow these problems through and you will not only increase your ability to think in abstractions, but you will enjoy solving murder problems and robberies, see which fishermen are liars and how a blind man can identify color purely by logic, and enjoy dozens of interesting situations. Puzzles range from easy to relatively difficult, and will please both beginners and experts.
About the Author: The late C. R. Wylie, Jr., taught for many years at the University of Utah, where he was Chairman of the Department of Mathematics.

A Dover Original
Clarence Raymond Wylie, Jr., had a long career as a writer of mathematics and engineering textbooks. His Advanced Engineering Mathematics was the standard text in that field starting in the 1950s and for many decades thereafter. He also wrote widely used textbooks on geometry directed at students preparing to become secondary school teachers, which also serve as very useful reviews for college undergraduates even today. Dover reprinted two of these books in recent years, Introduction to Projective Geometry in 2008 and Foundations of Geometry in 2009.

The author is important to our program for another reason as well. In 1957, when Dover was publishing very few original books of any kind, we published Wylie's original manuscript 101 Puzzles in Thought and Logic. The book is still going strong after 55 years, and the gap between its first appearance in 1957 and Introduction to Projective Geometry in 2008 may be the longest period of time between the publication of two books by the same author in the history of the Dover mathematics program. Wylie's 1957 book launched the Dover category of intriguing logic puzzles, which has seen the appearance of many books by some of the most popular authors in the field including Martin Gardner and, more recently, Raymond Smullyan.

Here's a quick one from 101 Puzzles in Thought and Logic:

If it takes twice as long for a passenger train to pass a freight train after it first overtakes it as it takes the two trains to pass when going in opposite directions, how many times faster than the freight train is the passenger train?

Answer: The passenger train is three times as fast as the freight train.