The Guinness Book of
Mind Benders

The following 13 puzzles are re-printed (with permission) from the book mind benders by Robert Eastaway and David Wells which contains 109 puzzles. The book is available in the bookshops for £4.99

T-shirt Teaser
Scruffy Sam has put on his T-shirt. Unfortunately it is inside out and back to front. Normally the washing label is on the inside of the left sleeve. Where is it now?
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Number Anagram
Claire has put some letter blocks together to make the following sum:
ONE + TWELVE = THIRTEEN
Nicola uses all these blocks but rearranges some of them to get a different sum, which is also correct. Then Claire replaces the I with the E and inserts another + block. She rearranges the blocks again and once more the result is correct. Can you find the two new versions?
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Can you do it?
You have a cylindrical can of the sort that baked beans are sold in. You want to fill it exactly one quarter full of water but you have no measuring instrument and the can is not graduated in any way (though you can scratch it yourself if you wish). How should you proceed
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Polar bearings
You are travelling to the North Pole by sled, but your huskies are too enthusiastic and you overshoot the Pole slighty. Will east be to your left or right?
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A Minor case
Sherlock Holmes was investigating what appeared to be a very minor break-in, as a favour to a friend. "Even you, my dear Watson", he began, "can solve this case by attentively observing the rather scuffed footprints that proceed through the scullery door, and along the hall, and disappear into the room on the left. What do you see?" "Er they're muddy?" ventured Watson. "Think logically Watson!" urged Holmes. "They proceed right foot, right foot, left foot, left foot, right, right, left, left and so on. What do you see now?" At last he understood. What had Watson realized?
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A Minor case

Sherlock Holmes was investigating what appeared to be a very minor break-in, as a favour to a friend. "Even you, my dear Watson", he began, "can solve this case by attentively observing the rather scuffed footprints that proceed through the scullery door, and along the hall, and disappear into the room on the left. What do you see?"
"Er they're muddy?" ventured Watson.
"Think logically Watson!" urged Holmes. "They proceed right foot, right foot, left foot, left foot, right, right, left, left and so on. What do you see now?"

At last he understood. What had Watson realized?

answer

Fun run go slow
This is Angela's first time in the three-mile Fun Run, and she is finding it a little tough. In fact she has only just completed the first two miles, and as she looks at her watch she says to herself (breathlessly), I'm only averaging four miles an hour. Oh dear, I wanted to average six miles per hour for this run - I must go a bit faster. How fast will she have to run the final mile in order to get her average speed for the whole Fun Run up to six miles per hour?
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Fun run go slow

This is Angela's first time in the three-mile Fun Run, and she is finding it a little tough. In fact she has only just completed the first two miles, and as she looks at her watch she says to herself (breathlessly), I'm only averaging four miles an hour. Oh dear, I wanted to average six miles per hour for this run - I must go a bit faster.

How fast will she have to run the final mile in order to get her average speed for the whole Fun Run up to six miles per hour?

answer

Name prediction
Jane Higgins was walking down the high street when she bumped into an old friend. "Hello, I haven't seen or heard from you since graduation back in 1982!" said Jane, "what's happened to you?" "Well, I got married in 1989 to somebody you wouldn't know. This is our son", said the friend who was holding hands with a little boy. "Hello and what's your name?" said Jane to the boy. "It's the same as Daddy's". "Ah so it's Peter is it?" said Jane How did Jane know?
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Name prediction

Jane Higgins was walking down the high street when she bumped into an old friend. "Hello, I haven't seen or heard from you since graduation back in 1982!" said Jane, "what's happened to you?"
"Well, I got married in 1989 to somebody you wouldn't know. This is our son", said the friend who was holding hands with a little boy.
"Hello and what's your name?" said Jane to the boy.
"It's the same as Daddy's".
"Ah so it's Peter is it?" said Jane

How did Jane know?

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Mum's secret
How old are you, Mum? I'm 35 But you've been 35 for years Yes, but this time it's true. I'm just ignoring the weekends. How old is Mum?
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Turn four into five
It is not too difficult to get from TWO to SIX by changing one letter at a time, each time making a proper word, like this:
TWO TOO TOP TIP SIP SIX
So TWO to SIX can be done in five steps. FOUR to FIVE takes longer. How many steps do you need to turn FOUR into FIVE? Can you do it with every letter changing at least once, including the F? How about turning ONE into TWO? And as a final very tough challenge, can you turn SEVEN into EIGHT? (Our solution has the rare word REVET in the middle.)
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Magic beans
"So you don't believe that I can use telepathy to count things?" said Uncle Norman. "OK, pick up any number of beans in your left hand (don't tell me how many!) and pick up the same number in your right hand. Now take four from your left hand and put them in your right hand. Count how many there are remaining in your left hand, put them back in the jar and put the same number from your right hand back in the jar. Now pick five more beans up in your left hand. I can now tell you that you have a total of" ... (Uncle Norman concentrated hard) ..."13 beans in your hands." He was right! How did Uncle Norman pull off this amazing bit of psychic counting?
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Magic beans

"So you don't believe that I can use telepathy to count things?" said Uncle Norman. "OK, pick up any number of beans in your left hand (don't tell me how many!) and pick up the same number in your right hand. Now take four from your left hand and put them in your right hand. Count how many there are remaining in your left hand, put them back in the jar and put the same number from your right hand back in the jar. Now pick five more beans up in your left hand. I can now tell you that you have a total of" ... (Uncle Norman concentrated hard) ..."13 beans in your hands."

He was right!
How did Uncle Norman pull off this amazing bit of psychic counting?

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True or False

In the box below, which of the statements is true, and which is false?

The number of false statements in this box is one
The number of false statements in this box is two
The number of false statements in this box is three
The number of false statements in this box is four

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Christmas card mystery
Last Christmas the Crown and Greyhound pub was selling its own cards. Cards were sold separately and, in theory, you could ask for whatever number of cards you wanted. Among other combinations, many customers bought multiples of 5 cards: a lot bought 5, some bought 15 and a few bought 20. What seemed odd, though is that nobody at all bought ten cards. Can you think of a simple explanation for this, other than coincidence.
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Christmas card mystery

Last Christmas the Crown and Greyhound pub was selling its own cards. Cards were sold separately and, in theory, you could ask for whatever number of cards you wanted. Among other combinations, many customers bought multiples of 5 cards: a lot bought 5, some bought 15 and a few bought 20. What seemed odd, though is that nobody at all bought ten cards. Can you think of a simple explanation for this, other than coincidence.

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Fair prizes
Four girls at the back of the classroom were comparing the numbers of prizes they had won at the fair. "I've got one more than you", said Bernice. "I've got two more than you", said one girl to another. "I've got three more than you" said one to another. "I've got four more than you" , "I've got five more than you", "I've got six more than you", rang their excited voices, but we don't know who was talking to whom. If they had won a total of 27 prizes, how many did Bernice win?
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Fair prizes

Four girls at the back of the classroom were comparing the numbers of prizes they had won at the fair. "I've got one more than you", said Bernice. "I've got two more than you", said one girl to another. "I've got three more than you" said one to another. "I've got four more than you" , "I've got five more than you", "I've got six more than you", rang their excited voices, but we don't know who was talking to whom.

If they had won a total of 27 prizes, how many did Bernice win?

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By-election Blues
"What can you tell me about our party's potential candidates for the by-election, Peter?" asked Humphrey Dimpsworth, the local party chairman, counting up the number on the list. "Well, I have good news and bad news. The good news is that I've had some research done to see if they meet our usual criteria, and we've discovered that eight of them are happily married at the moment, seven of them were not involved in that council scandal four years ago, and six of them have never been involved in any lunatic fringe activities." "Excellent, lets see, that means at the very minimum one of the candidates must have all of these virtues. What's the bad news?" "Er well, you're right, but unfortunately there is only one candidate who has all three virtues - and that is your old sparring partner Henrietta Prigg." How many candidates were there in total?
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By-election Blues

"What can you tell me about our party's potential candidates for the by-election, Peter?" asked Humphrey Dimpsworth, the local party chairman, counting up the number on the list.
"Well, I have good news and bad news. The good news is that I've had some research done to see if they meet our usual criteria, and we've discovered that eight of them are happily married at the moment, seven of them were not involved in that council scandal four years ago, and six of them have never been involved in any lunatic fringe activities."
"Excellent, lets see, that means at the very minimum one of the candidates must have all of these virtues. What's the bad news?"
"Er well, you're right, but unfortunately there is only one candidate who has all three virtues - and that is your old sparring partner Henrietta Prigg."

How many candidates were there in total?

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Coloured hats
Professor Pots has set a tough challenge for his four brightest students, who are sat facing each other. He says "I have seven hats here, four black and three white. I will blindfold you and then give you each a hat. I will then remove the blindfolds and ask each of you in turn if you are able to work out what is the colour of your hat." He does this. Each student thinks very hard before he speaks. And this is what each one says: First student: "I don't know." Second student: "I don't know either." Third student: "Nor do I." Before his blindfold is removed, the fourth student announces the colour of his hat. What is it and how does he know?
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Coloured hats

Professor Pots has set a tough challenge for his four brightest students, who are sat facing each other. He says "I have seven hats here, four black and three white. I will blindfold you and then give you each a hat. I will then remove the blindfolds and ask each of you in turn if you are able to work out what is the colour of your hat."
He does this. Each student thinks very hard before he speaks. And this is what each one says:
First student: "I don't know."
Second student: "I don't know either."
Third student: "Nor do I."
Before his blindfold is removed, the fourth student announces the colour of his hat.
What is it and how does he know?

answer

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The Guinness Book of Mind Benders

T-shirt Teaser

Number Anagram

Can you do it?

Polar bearings

A Minor case

Fun run go slow

Name prediction

Mum's secret

Turn four into five

Magic beans

True or False

Christmas card mystery

Fair prizes

By-election Blues

Coloured hats

The Guinness Book of
Mind Benders