From John Boyce Bennett’s 1980 logic textbook Rational Thinking:
If it’s false that no dopips are fraks, characterize each of these propositions as true, false, or doubtful:
a. All dopips are fraks.
b. Few dopips are fraks.
c. Some dopips are fraks.
d. No fraks are dopips.
e. Some dopips are not fraks.
A curious puzzle by Stanley Rabinowitz, from the Spring 1984 issue of Pi Mu Epsilon Journal:
In the little hamlet of Abacinia, two different base systems are used, and everyone speaks the truth. One resident said, “26 people use my base, base 10, and only 22 people speak base 14.” Another said, “Of the 25 residents, 13 are bilingual and 1 is illiterate.” How many people live in Abacinia?
A problem from the October 1964 issue of Eureka, the journal of the Cambridge University Mathematical Society:
“At noon precisely, a train leaves A for B, and another leaves B for A. They pass after 51 minutes. Each train stays 27 minutes at its destination and then returns by the same route. The trains from A and B travel throughout with constant speeds of 23 m.p.h. and 39 m.p.h., respectively. At what time do they pass for the second time?”
Currier & Ives published this lithograph in 1875: “Six moral sentences beginning with the letter T.” I can’t find the answers! My guesses:
True honesty brings prosperity.
Trace[?] the footsteps of the wise.
Those do well who never lie.
Tears of repentency are like diamonds.
Train yourself to be temperate.
That which is well earned is most comforting[?].
From John Scott’s The Puzzle King, 1899:
“A locomotive with a truck is travelling over a straight level line at the rate of 60 miles an hour. A man standing at the extreme rear of the truck casts a small stone into the air in a perpendicular direction. The stone travels upward at an average rate of 30 feet per second for 3 seconds; the height of the man’s hand from ground when the stone leaves is 15 feet. At what distance behind the train will the stone strike the ground in its descent?”
This logic puzzle game was invented by Israeli mathematician Gyora Benedek. The task is simple: Write a number in each blank square so that, in the finished diagram, a continuous chain of consecutive numbers connects the lowest number, 1, to the highest, 40. The numbers can connect horizontally, vertically, or diagonally. For example, the number 8 must go in the square above 7 because 7, 8, and 9 must occupy adjacent squares. Can you complete the rest of the diagram?
You’ve dealt about half the cards for a bridge game when you’re momentarily called away. When you return, no one can remember where you left off dealing. Without counting cards, how can you finish the deal accurately, so that each player receives the cards she’d have got if you hadn’t been interrupted?
From The Third Penguin Problems Book, 1946: What does this say?
FORSIFROMDEMATION FEWER ABERDETHATEN HABITATHENTS TEARENT CRONEASING COMETHEIRS.
Wei-Hwa Huang offered this brilliant crossword in the May 2008 issue of Word Ways:
Across
1 Sticks
6 Farm animals
7 Ogles
8 Leisure
9 Ride
Down
1 Soothe
2 Peaceful
3 Reserved
4 Untroubled
5 Pacify
