The Great Book of Riddles: 250 Magnificent Riddles, Puzzles and Brain Teasers (Elsinore Puzzles) Read online

  A Short Introduction

  This book presents 250 of the greatest riddles and puzzles we know. Some of them are thousands of years old; others were created especially for this book, and have never appeared in print before.

  Our aim was create a compendium of riddles and puzzles that would bring enjoyment to people of all ages. As such, we have tried to include as wide a variety of puzzles as possible. There are classical logic puzzles, lateral thinking puzzles, “who am I?” riddles, mathematical brain teasers, word ladders, ditloids, and a large selection of illustrated pen and paper, coins, cups, and toothpicks puzzles. This is the first time a collection of such breadth has been compiled and formatted especially for Kindle devices. The puzzles have been carefully organized into 25 chapters, and each question is hyperlinked to its solution, to provide utmost ease of navigation.

  We hope you will enjoy unraveling these riddles as much as we enjoyed creating and editing them. We wish you good luck, and the strength to resist turning to the solution too soon,

  Peter Keyne and Rudolph Amsel

  Copyright © Elsinore Books 2014

  How to use this book

  This book has been created especially for Kindle, and we have tried to make it as easily navigable as possible. You can view the solution to each puzzle by clicking on the question number. You can return to the question by pressing the “back” key on your kindle. Clicking on the chapter title will always take you back to the contents page.

  Other Titles by Elsinore Books:

  The Little Book of Capital Cities

  Guess the Initials Quiz

  The Best of Poetry: Thoughts that Breathe

  Table of Contents

  A Short Introduction

  Table of Contents

  Round 1: Old Chestnuts Warmed Up

  Round 2: Pure Logic 1

  Round 3: Coins, Cups and Toothpicks

  Round 4: Words Words Words 1

  Round 5: A Different Way of Seeing

  Round 6: The Tale’s the Thing: Lateral Thinking Puzzles 1

  Round 7: What am I? Painting Word Pictures

  Round 8: Number Puzzlers

  Round 9: Brainbats

  Round 10: Pure Logic 2

  Round 11: Listen Carefully

  Round 12: Words Words Words 2

  Round 13: Pen and Paper

  Round 14: What am I? New Riddles

  Round 15: Ditloids

  Round 16: Number Puzzlers 2

  Round 17: Pure Logic 3

  Round 18: Plain Ridiculous!

  Round 19: The Great Riddles from Literature

  Round 20: Outside the Box

  Round 21: The Tale’s the Thing: Lateral Thinking Puzzles 2

  Round 22: Contradictories

  Round 23: Coins, Cups and Toothpicks 2

  Round 24: Words, Words, Words 3

  Round 25: Pure Logic 4

  Thank You for Reading

  Other Titles by Elsinore Books

  Illustrations

  Round 1: Old Chestnuts Warmed Up

  These ten introductory riddles are likely to be familiar to most puzzle lovers. Some require straightforward logical reasoning; others depend on word-play and are best approached from a different angle. Together they should serve as a good warm-up for what follows. Good luck!

  1. Two Fathers and Two Sons

  Two fathers and their two sons go fishing together. They each catch one fish to take home with them. They do not lose any fish, and yet when they arrive at home they only have three fish. How can this be?

  2. A Curious Object

  The man who makes it doesn’t use it; the man who buys it doesn’t need it; the man who uses it doesn’t know it. What is it?

  3. A Companion Riddle

  Whoever makes it, tells it not; whoever takes it, knows it not; and whoever knows it, wants it not. What is it?

  4. Legal loophole

  Why can’t a man living in California be legally buried in New York (even if it’s left as an instruction in his will)?

  5.The Farmer’s Challenge

  A farmer went to market and purchased a fox, a goose, and a bag of corn (for reasons that must forever remain his own). On his way home, he needed to cross a river, but the boat he found there was so tiny, it could only carry the farmer himself and a single one of his new possessions. Naturally he couldn’t leave the fox alone with the goose; or the goose alone with the bag of corn. The only things he could safely leave together were the fox and the bag of corn, for a fox will never be tempted to eat corn, and only very rarely will a bag of corn be tempted to eat a fox.

  The farmer’s challenge was this: how could he ferry all of his possessions across the river, without harm coming to any of them?

  6. The Riddle of the Sphinx

  What walks on four legs in the morning; three legs at midday; and two legs in the evening?

  7. Medical Mystery

  A boy and his father are involved in a traffic accident, and the father dies. The boy is rushed to hospital, suffering from injuries. The Head Surgeon is called to operate, but on seeing the boy, immediately declares: “I cannot operate. This boy is my son.” How is this possible?

  8. The Labyrinth

  Identical twins — A liar and a truth teller — stand at a fork of the path in a labyrinth. One path leads out of the labyrinth, but the other leads further into it, and following it would be ill-advised to say the least. You do not know which of the twins is the liar and which is the truth teller, but you know that they both know the way out of the labyrinth and are aware of the other’s behavior.

  You may ask only one question to only one of the twins. What should you ask to escape the labyrinth?

  9. On Friday

  A man rides into an inn on Friday, stays for three nights and rides out again on Saturday. How can this be?

  10. A Journey to St. Ives

  As I was going to St. Ives,

  I met a man with seven wives.

  Each wife had seven sacks.

  Each sack had seven cats.

  Each cat had seven kits.

  Kits, cats, sacks, and wives;

  How many were going to St. Ives?

  Answers: Round 1

  1. Two fathers and two sons refers to just three people — A grandfather, his son, and his grandson. Two of the three are fathers; and two of the three are sons.

  2. A Coffin

  3. Counterfeit money

  4. Because he’s alive.

  5. The farmer should take the following seven steps:

  1. Take the goose across

  2. Return

  3. Take either the fox or the corn across and…

  4. Return with the goose

  5. Take either the fox or the corn across

  6. Return

  7. Take the goose across

  6. Man; who crawls on all fours as an infant; walks on two feet as an adult; and uses a walking stick in old age.

  This is the most famous riddle from Greek mythology. According to most sources, the riddle was posed by a sphinx guarding the gates to the Greek city of Thebes. When Oedipus solved it, the sphinx devoured herself, and the city was liberated.

  7. The Head Surgeon is the boy’s mother.

  8. Ask either of the twins: “Which path would your twin say leads to the exit?” Then take the opposite path. It does not matter which twin you ask – they will point in the same direction:

  The truth teller knows his twin would point to the wrong path and as he himself is truthful,
he points to the wrong path.

  The liar knows his twin would point to the right path, but as he lies about everything, he lies about this too, and points to the wrong path.

  They are both guaranteed to point to the wrong path in answer to this question; so you will be guaranteed to find the exit by taking the other path.

  An alternative answer:

  Ask either of the twins: "If I were to ask you which path led to the exit, what would you say?" In answer to this question, both of the twins will point to the correct path.

  9. Friday is the name of the man’s horse. He arrived at the inn on Wednesday, stayed Wednesday, Thursday, and Friday night, and left on Saturday.

  10. One — At least this is the most satisfying answer; and based on the assumption that the people the narrator encounters are heading in the opposite direction. However, there is enough ambiguity in the wording of this riddle to yield several other answers, including: 2802 if the narrator overtook the group on the way to St. Ives; and 2800 if we only count “Kits, cats, sacks, wives” and exclude the narrator and the man.

  *Illustrations

  Round 2: Pure Logic 1

  1. A Chess Problem

  If a standard 8x8 chessboard has two of its diagonally opposite corners removed, is it possible to place 31 dominoes so as to cover all of the remaining 62 squares?

  2. Awkward Age

  A girl was ten on her last birthday, and will be twelve on her next birthday. How is this possible?

  3. Rising Tide

  A ladder hangs over the side of a ship anchored in port. The bottom rung of the ladder touches the water. The distance between rungs is 30cm, and the length of the ladder is 270cm.

  If the tide is rising at a rate of 15cm per hour, how long will it be before the water reaches the top rung?

  4. The Bag of Counterfeit Coins

  There are ten bags of coins in front of you. Nine of them contain genuine coins but one of them, you know, is full of counterfeit coins. You cannot see any difference between the coins or bags, or feel any difference when you lift them. However, you know that the counterfeit coins weigh one gram less than the real coins.

  You have an accurate scale, but are only allowed one weighing to determine which of the ten bags contains counterfeit coins. How should you proceed?

  5. Head Start

  Usain and Mo race one another over 100m. When Usain crosses the finish line, Mo is only at the 90m mark. They agree to have a second race, but to make it fairer, Usain will begin 10m behind the starting line. All things being equal, who would you expect to win the race?

  6. A Famous Portrait

  A man is shown a portrait painting. He looks closely, then exclaims rather cryptically: “Brothers and sisters have I none, but that man’s father is my father’s son.”

  Who is the man in the portrait?

  7. Jewel Thieves

  There may not be honor among thieves, but there is certainly hierarchy, and it pays to be at the top. Four thieves were planning to break into the king’s jewel room, and had agreed among themselves to enter one at a time and each take half of however many jewels they found there. The first thief entered the jewel room, filled his pockets as agreed, and was about to make off, when he realized that he would be leaving the second thief with an impossible division. “Well, to make things easier for him” he thought “I had better take another jewel”, and that’s exactly what he did. The second thief entered the room, took his half of the jewels, and encountering the same problem of division, resolved on the same solution, and also took one jewel more. The third thief followed suit, taking half, and one jewel more. At last, it was the fourth thief’s turn, but when he entered — alas! — he saw that all the jewels were gone.

  How many jewels were there to begin with?

  8. Barbershop Duet

  A man arrives in a small town in the middle of nowhere and is in desperate need of a haircut. He observes that there are only two barbers in the town. The East Side Barber is immaculately presentable, and perfectly groomed. Coincidentally, he has the very haircut the man wishes for himself. The West Side Barber, the man sees to his dismay, is poorly dressed and in desperate need of a shave. He has an awful shock of hair the man wouldn’t wish upon his worst enemy. Which barber shop does he decide to visit and why?

  9. The Missing Dollar

  Three guests check into a hotel room. The manager informs them that it will cost $30, so they each pay $10. A little later however, the manager realizes that he has made a mistake; the room only costs $25 dollars! He calls the bellboy and gives him $5 to return to the guests.

  On the way to the room, it occurs to the Bellboy that $5 cannot be evenly divided between the three guests, and he decides to save them the trouble of arguing over its division by pocketing $2 dollars for himself. He then gives each of the guests $1 back.

  As each guest paid $10 initially and received $1 back, in effect, they each paid $9.

  $9 multiplied by 3 is $27, and the bellboy took $2 for himself.

  $27 +$2 = $29. So who has the missing dollar?

  10. Three Switches — One Light

  There are three light switches outside a room. Inside is a single light bulb, controlled by one of the three switches. You need to determine which switch operates the bulb.

  You can turn the switches on and off as many times as you wish (they are all off to begin with), but may only enter the room once. There is no one there to help you. The door to the room is closed, and there are no windows, so you cannot see inside. How can you discover which switch operates the bulb?

  Answers: Round 2

  1. No. The simplest proof is that every domino must cover one black square and one white square. The diagonally opposite corners of a chess board are the same color, so removing them would leave an imbalanced number of black and white squares (either 32 white and 30 black; or 32 black and 30 white).

  2. Today is her eleventh birthday

  3. The ship will rise with the tide, so the water will always remain level with the first rung.

  4. Number the bags from 1-10, then remove one coin from the first bag, two from the second, three from the third etc. all the way up to the tenth bag. Next weigh the coins you have removed. Their total weight will be somewhere between 1 and 10 grams lighter than it would have been if all the coins were genuine. If it is one gram too light, the counterfeit coin came from the first bag; two grams too light, and they came from the second bag etc. all the way up again to the tenth bag.

  5. Assuming that Usain does not slow down through tiredness in the final 10m, he will win this race as well. At the 90m mark they will be neck and neck (Usain having covered 100m and Mo 90m as in their previous race), and Usain will be faster over the final 10m.

  6. The man is looking at a portrait of his own son.

  7. 14. The answer is easily calculated if you work backwards:

  The third thief must have found two jewels; the second thief, six; and the first thief, fourteen.

  8. The West Side Barber. The man reasons that as there are only two barbers in town, they must cut each other’s hair.

  9. This is not a paradox, and relies on misdirection from the teller.

  If we examine the initial transaction correctly we find:

  $30 (initial payment) = $25 (to the hotel) + $2 (to the bellboy) + $3 (refund)

  Confusion arises because the listener is encouraged to add the $2 stolen by the bellboy to the $27 paid by the guests, and arrive at $29. There is no reason to make this calculation, as the bellboy’s $2 is already included in the guests’ $27 payment. When the guests receive their refund, they have indeed paid $27, but only $25 has gone to the hotel.

  The $27 is accounted for as follows:

  $27 (payment after receiving refund) = $25 to the hotel + $2 to the bellboy

  10. Take the following steps:

  1. Turn two switches ON, and leave one switch OFF.

  2. Wait five minutes.

  3. Turn one switch from ON to OFF. (One switch is now
ON and two are OFF)

  4. Enter the room.

  a) If the light bulb is ON, it is operated by the switch you left ON.

  b) If the light bulb is OFF, touch it.

  If it is warm it is operated by the switch you turned ON and OFF.

  If it is cold, it is operated by the switch you never turned ON.

  *Illustrations

  Round 3: Coins, Cups and Toothpicks

  1. Coin Triangle

  How can you reverse the triangle by moving only three coins?

  2. Three Coin Logic

  There are three coins in front of you. One is gold; one is silver; one is bronze. You are asked to make one statement. If what you say is true, you will receive one of coins. If what you say is false, you will get nothing. What can you say to guarantee you receive the gold coin?

  3. Jumping Coins

  Ten coins are placed in line as shown above. The challenge is to rearrange the coins into five stacks of two coins, and do so in only five moves. A move is completed when a coin jumps to the right or left over two coins to land on a single coin. For example, the coin at position 6 could jump to the left over two coins to land on the coin a position 3. The coin at position 2 could then jump over the new stack at position 3 to land at position 4.

  4. Coins and Cups