I
N
N
O
V
A
T
I
O
N
P
U
Z
Z
L
E
S
2
Content
100 Factorial ....................................................................................................................... 4
4 men in hats ....................................................................................................................... 5
A Puzzle by Lewis Carroll .................................................................................................. 7
Actual Newspaper Headlines .............................................................................................. 8
Anthony and Cleopatra ....................................................................................................... 9
Bottled Money .................................................................................................................. 10
Circles ............................................................................................................................... 11
Coin Balance ..................................................................................................................... 12
Count the faces .................................................................................................................. 14
Crossing the bridge ........................................................................................................... 15
Death in a Field ................................................................................................................. 16
Drinking Glasses ............................................................................................................... 17
Falling Wine...................................................................................................................... 18
Family Problems ............................................................................................................... 19
Friday ................................................................................................................................ 20
Gaining Space ................................................................................................................... 21
Heaven .............................................................................................................................. 22
How many stamps ............................................................................................................. 23
Light Switches .................................................................................................................. 24
Manhole Covers ................................................................................................................ 25
Matches Puzzle 1 .............................................................................................................. 26
Matches Puzzle 2 .............................................................................................................. 27
Matches Puzzle 3 .............................................................................................................. 28
From Mycoted ........................................................................................................... 28
Matches Puzzle 4 .............................................................................................................. 29
From Mycoted ........................................................................................................... 29
Matches Puzzle 5 .............................................................................................................. 30
From Mycoted ........................................................................................................... 30
Matches Puzzle 6 .............................................................................................................. 31
From Mycoted ........................................................................................................... 31
Matches Puzzle 7 .............................................................................................................. 32
From Mycoted ........................................................................................................... 32
Matches Puzzle 8 .............................................................................................................. 33
From Mycoted ........................................................................................................... 33
Maths Product ................................................................................................................... 34
From Mycoted ........................................................................................................... 34
Nine Dots .......................................................................................................................... 35
From Mycoted ........................................................................................................... 35
Physics Problems .............................................................................................................. 38
From Mycoted ........................................................................................................... 38
Push that Car ..................................................................................................................... 41
Quick Quiz ........................................................................................................................ 42
3
Sheep ................................................................................................................................. 45
Sheep Pens ........................................................................................................................ 46
Straight Lines .................................................................................................................... 48
Summer Months ................................................................................................................ 49
The Arm of the Postal Service .......................................................................................... 50
The Blind Beggar .............................................................................................................. 51
The Broken Match ............................................................................................................ 52
The Coal, Carrot and Scarf ............................................................................................... 53
The Deadly Dish ............................................................................................................... 54
The Deadly Party .............................................................................................................. 55
The Elder Twin ................................................................................................................. 56
The Man in the Bar ........................................................................................................... 57
The Man who Hanged Himself ......................................................................................... 58
The Music Stopped ........................................................................................................... 59
The Realisation ................................................................................................................. 60
The Royal Mint ................................................................................................................. 61
The Swimmer in the Forest ............................................................................................... 62
The bird and the cars ......................................................................................................... 63
The man in the Elevator .................................................................................................... 64
There are many correct ways to answer a test question .................................................... 65
Three Men at a Hotel ........................................................................................................ 67
Triangle Ratios .................................................................................................................. 68
Trouble with Sons ............................................................................................................. 69
Wetter as it Dries .............................................................................................................. 70
What is it... ........................................................................................................................ 71
4
100 Factorial
From Mycoted
One for the mathematicians this week, with thanks to Paul Kellet for sending it in.
How many zeros are there at the end of 100! (factorial)?
Answer
24
The trick here is not to calculate 100! on your calculator (which only gives you ten digits
of accuracy), but to figure out how high a power of 10 goes into 100! evenly. For every
trailing zero, there is a power of 10 that divides 100! evenly. In order to do that, since 10
= 2*5, we need to figure the highest powers of 2 and 5 dividing 100! and take the lesser
of the two exponents.
(Why?) Consider what happens when we multiply together 1*2*3*4*5*6*..., starting
with the lowest numbers first. Every fifth number, starting with 5, is divisible by 5. That
gives you 100/5 = 20 factors of 5 in 100!. But there are more. Every 25th number,
starting with 25, has an extra factor of 5 beyond the ones already counted. That gives
you 100/25 = 4 more factors of 5 in 100!. To get a third factor of 5 from a single number,
it has to be a multiple of 125, and no number <= 100 is, so that is all.
The answer is: [100/5] + [100/5^2] + [100/5^3] + ... = 20 + 4 + 0 + ... = 24
Here [x] means the integer part of x, or the greatest integer not exceeding x.
(Why do we use this [x] instead of x?) All the terms from some point on will be zero, so
this is a finite sum. Now for 2's (or any other prime number), the same analysis holds.
The answer for the highest power of 2 dividing 100! is [100/2] + [100/2^2] + [100/2^3]
+ [100/2^4] + ... = 50 + 25 + 12 + 6 + 3 + 1 + 0 + 0 + ... = 97 The smaller of the two is
24, so the highest power of 10 dividing 100! is 10^24, so 100! ends with 24 zeroes.The
same analysis works for any factorial n! and any prime p. The highest power of p
dividing n! is: [n/p] + [n/p^2] + [n/p^3] + [n/p^4] + ...
5
4 men in hats
From Mycoted
Shown above are 4 men buried up to their necks in the ground. They cannot move so can
only look forward. Between A and B is a brick wall which cannot be seen through. They
all know that between them they are wearing 4 hats, 2 x black and 2 x white, but they do
not know what colour they are wearing. In order to avoid being shot one of them must
call out to the executioner the colour of their hat. If they get it wrong, everyone will be
shot. They are not allowed to talk to each other and have 10 minutes to fathom it out.
After 1 minute, one of them calls out.
Question: Which one of them calls out?
Question: Why is he 100% certain of the colour of his hat?
This is not a trick question. There are no outside influences nor other ways of
communicating. They cannot move and are buried in a straight line. So A & B can only
see their respective sides of the wall, C can see B, and D can see B & C
Answer
6
C calls out that he is wearing a black hat. Why is he 100% certain of the colour of his
hat ?
After a while, C comes to the realization that he must answer.
This is because D can't answer, and neither can A or B.
D can see C and B, but can't determine his own hat colour. B can't see anyone and also
can't determine his own hat colour. A is in the same situation as B, where he can't see
anyone and can't determine his own hat colour.
Since A, B, and D are silent, that leaves C. C knows he is wearing a black hat because if
D saw that both B and C were wearing white hats, then he would have answered. But
since D is silent, C knows that he must be wearing a black hat as he can see that B is
wearing a white hat.
7
A Puzzle by Lewis Carroll
From Mycoted
John gave his brother James a box:
About it there were many locks.
James woke and said it gave him pain;
So gave it back to John again.
The box was not with lid supplied
Yet caused two lids to open wide:
And all these locks had never a key
What kind of box, then, could it be?
Answer
As curly haired James was sleeping in bed,
His brother John gave him a blow on the head.
James opened his eyelids, and spying his brother,
Doubled his fists, and gave him another.
This kind of a box then is not so rare
The lids are the eyelids, the locks are the hair.
8
Actual Newspaper Headlines
From Mycoted
OK, not really puzzles, but a few headlines that show things can be read in more than one
way.































Something went wrong in jet crash, experts say
Police begin campaign to run down jaywalkers
Safety Experts say school bus passengers should be belted
Drunk gets nine months in violin case
Survivor of siamese twins joins parents
Farmer Bill dies in house
Iraqi head seeks arms
Is there a ring of debris around Uranus?
Stud tires out - Prostitutes appeal to Pope
Panda mating fails; Veterinarian takes over
Soviet virgin lands short of goal again
British left waffles on Falkland Islands
Eye drops off shelf
Teacher strikes idle kids
Reagan wins on budget, but more lies ahead
Squad helps dog bite victim
Shot off woman's leg helps Nicklaus to 66
Enraged cow injures farmer with axe
Plane too close to ground, crash probe told
Miners refuse to work after death
Juvenile court to try shooting defendant
Stolen painting found by tree
Two soviet ships collide, one dies
2 sisters reunited after 18 years in checkout counter
Killer sentenced to die for second time in 10 years
Never withhold herpes infection from loved one
Drunken drivers paid $1000 in '84
War dims hope for peace
If strike isn't settled quickly, it may last a while
Cold wave linked to temperatures
Enfiels couple slain; Police suspect homicide
9
Anthony and Cleopatra
From Mycoted
Anthony and Cleopatra are lying dead on the floor of a villa in Egypt. Nearby is a broken
bowl. There is no mark on either of their bodies and they were not poisoned. How did
they die?
Answer
Anthony and Cleopatra were goldfish whose bowl was knocked over by a clumsy dog.
This is one of a set of puzzles which deceive by using human names for animals. This is
not a very satisfactory basis for a good puzzle but despite that, the puzzle has enduring
popularity.
10
Bottled Money
From Mycoted
If you put a small coin into an empty wine bottle and replace the cork, how would you
get the coin out of the bottle without taking out the cork or breaking the bottle?
Answer
Push the cork into the bottle, and shake out the coin.
11
Circles
From Mycoted
Is the inner shape rearly a circle?
Answer
Both 'circles' are perfect circles.
Sometimes it is difficult to see the wood for the trees, and 'information' around the object
or problem you are interested in can distort your view. Try covering the lines with a
piece of card, or when looking at a problem try and remove some of the 'non-relevant
information'.
12
Coin Balance
From Mycoted
There are 12 boxes each containing a coin. There are a total of 11 pennies and 1 other
coin in the boxes. You have a balance scale for comparing the weight of the boxes in
which you can put any number of boxes on each side. You have at most, three weighings.
In these three weighings you must find out which of the 12 boxes has the coin that is not
a penny.
Answer
Balance any 4 coins (and call them A) with any other 4 coins (and call them B).
Case 1. - The coins balance. You now have a stock of 8 coins (A and B) you know are
ok. Weigh 3 good coins again 3 unknowns - if they balance then you have identified the
coin and can use the last balance to determine if it is heavy or light. If they don't balance
you know if it is heavy or light. Weigh 2 of the 3 unknown coins, and they will balance
(identifying the unknown coin) or not.
Case 2 - Left hand balance (A) is heavier. You have a stock of 4 known coins (C) and
8 unknown coins (A and B). Take 2 coins from group A (the left hand side) and 2 from
group B (the right hand side) and balance these with 1 coin from A, 1 from B and 2 from
C. If they balance, then the 4th coin from A or B is the unknown coin, and you can
balance with a good coin to determine which. If A1, A2, B1, B2 are lighter than A3, B3,
C1, C2 then either B1, B2 are lighter or A3 is heavier (and can be determined by a single
balance) If A1, A2, B1, B2 are heavier than A3, B3, C1, C2 then either A1, A2 are
heavier or B3 is lighter (and can be determined by a single balance)
Case 3 - Left hand balance (A) is lighter.
As case 2, but swap all heaver / lighter.
An alternative solution is often proposed (This only works if you know in advance
that the none-penny is heavier. As this is not stated in the puzzle it will not work in
all cases)
1. Divide the coins into two groups, each containing six coins. Weigh the two groups and
set aside the lighter group.
2. Divide the heavier group into two stocks, each containing three coins. Weigh these
13
two stocks, setting aside the lighter stock.
3. Weigh two coins from the heavier stock against each other. If either coin is heavier,
then the heavier coin is not a penny. If the coins weigh the same amount, then the third
coin in that stock is not a penny.
14
Count the faces
From Mycoted
How many faces can you see in the image?
Seven is good, but if you can see 10 you are doing better ...
15
Crossing the bridge
From Mycoted
"U2" has a concert that starts in 17 minutes and they must all cross a bridge to get there.
All four men begin on the same side of the bridge.You must help them across to the other
side. It is night. There is one flashlight. A maximum of two people can cross at one time.
Any party who crosses, either 1 or 2 people, must have the flashlight with them. The
flashlight must be walked back and forth, it cannot be thrown etc.
Each band member walks at a different speed. A pair must walk together at the rate of the
slower man's pace:
Bono:- 1 minute to cross Edge:- 2 minutes to cross Adam:- 5 minutes to cross Larry:-10
minutes to cross
For example: if Bono and Larry walk across first, 10 minutes have elapsed when they get
to the other side of the bridge. If Larry then returns with the flashlight, a total of 20
minutes have passed and you have failed the mission.
Note: There is no trick behind this. It is the simple movement of resources in the
appropriate order. There are two known answers to this problem. This is based on a
question Microsoft gives to all prospective employees.
Note: Microsoft expects you to answer this question in under 5 minutes! There are no
tricks to this like meeting halfway or anything. Good luck.
Answer
One solution is that;
1.
2.
3.
4.
5.
Bono & Edge cross = 2 mins (total = 2)
Bono goes back = 1 mins (total = 3)
Larry & Adam cross = 10 mins (total = 13)
Edge goes back = 2 mins (total = 15)
Bono & Edge cross = 2 mins (total = 17)
A 2nd version is swapping Bono and Edge.
16
Death in a Field
From Mycoted
A man is lying dead in a field. Next to him there is an unopened package. There is no
other creature in the field. How did he die?
Answer 1
There was a package dropped from an over flying Chopper. The packet hit the person in
the field and he was knocked dead.
Answer 2
The man had jumped from a plane but his parachute had failed to open. It is the
unopened package.
Answer 3
The man is highly allergic to plant growth in the field and it suffocated him. The
package is just something he was carrying and has no implication to the puzzle.
17
Drinking Glasses
From Mycoted
Six drinking glasses stand in a row, with the first three full of water and the next three
empty. By handling and moving only one glass at a time, how can you arrange the six
glasses so that no full glass stands next to another full glass, and no empty glass stands
next to another empty glass. What is the minimum number of moves to solve this puzzle.
Answer
The problem can be solved by moving one glass. Simply pick up the middle one of the
full glasses, pour the water into the middle one of the empty glasses, and return the glass
to it's original position.
18
Falling Wine
From Mycoted
Whilst in a balloon floating stationary off the coast of france, I dropped two wine bottles
over the side. If one was empty and the other full, which hit the ground first?
Answer
Neither hit the ground - I was off the coast of france, over the sea.
19
Family Problems
From Mycoted
Can you solve all of these in under 30 seconds?

A boy has as many sisters as he has brothers, but each of his sisters has twice as
many brothers as she has sisters. How many boys and girls are there in the
family?
Answer
There are 4 boys and 3 girls.

A man and his sister were out walking together one Saturday morning. The man
pointed across the street to a boy and said: ‘That boy is my nephew.’ The woman
replied: ‘He is not my nephew.’ Can you explain this.
Answer
The boy is the woman’s son.

Two Russians walk down a street in Moscow. One Russian is the father of the
other Russian’s son. How are they related?
Answer
They are husband and wife.
20
Friday
From Mycoted
A man rode into town on Friday. He stayed for three nights and then left on Friday. How
come?
Answer
The man's horse was called Friday. OK, so this is really a schoolboy riddle but people
keep asking it!
21
Gaining Space
From Mycoted
Answer
If you look closely at the hypotenuse (long) edge of the triangle, you will find that it is
not straight. In one case it is slightly concave (bends in) and in one case it is slightly
convex (bends out). The difference between these two, is the area of one square. Try
cutting them out of card and putting a ruler against the edge.
22
Heaven
From Mycoted
A man died and went to Heaven. There were thousands of other people there. They were
all naked and all looked as they did at the age of 21. He looked around to see if there was
anyone he recognised. He saw a couple and he knew immediately that they were Adam
and Eve. How did he know?
Answer
He recognised Adam and Eve as the only people without navels. Because they were not
born of women, they had never had umbilical cords and therefore they never had navels.
This one seems perfectly logical but it can sometimes spark fierce theological
arguments!
23
How many stamps
From Mycoted
If it takes twelve 1p stamps to make a dozen, how many 3p stamps are needed?
Answer
12 - there are still 12 in a dozen, many people try to divide 12 by 3 and say 4 stamps
make 12p, but that is not the question.
24
Light Switches
From Mycoted
Three switches outside a windowless room are connected to three light bulbs inside the
room. How can you determine which switch is connected to which bulb if you are only
allowed to enter the room once?
Answer
Switch on the first switch, leave it for a minute, and then switch it off again. Then switch
on the second switch and enter the room. The second switch will be connected to the
light that is on, the first switch will be connected to the light with the warm bulb, and the
third switch will be connected to the light with the cold bulb.
25
Manhole Covers
From Mycoted
Why is it better to have round manhole covers than square ones?
Answer
This is logical rather than lateral, but it is a good puzzle which can be solved by lateral
thinking techniques. It is supposedly used by a very well-known software company as an
interview question for prospective employees. Solution A square manhole cover can be
turned and dropped down the diagonal of the manhole. A round manhole cannot be
dropped down the manhole. So for safety and practicality, all manhole covers should be
round.
Another answer is also that they can be rolled around to save lifting them.....
26
Matches Puzzle 1
From Mycoted
Remove 8 matches to leave just 2 squares, which should not touch.
Answer
27
Matches Puzzle 2
From Mycoted
Move 3 matches so that the pattern points down instead of up.
Answer
28
Matches Puzzle 3
From Mycoted
Remove 1 match and rearrange the remainder to make 6 equal shapes.
Answer
29
Matches Puzzle 4
From Mycoted
Make 4 triangles, all the same size as the ones shown with only 6 matches.
Answer
30
Matches Puzzle 5
From Mycoted
Rearrange 3 matches to make 8 equilateral triangles.
Answer
31
Matches Puzzle 6
From Mycoted
Rearrange 2 matches to make 7 squares
Answer
32
Matches Puzzle 7
From Mycoted
Remove 2 matches to make 4 equal squares, with each match forming the side of a
square.
Answer
33
Matches Puzzle 8
From Mycoted
Form a bridge from the outer square to the inner square. As one match is exactly the
length between squares, there is no surplus to form a bridge. 2 matches cannot be used in
a straight line as there is nothing to support them where they join. What is the minimum
number of additional matches required?
Answer
34
Maths Product
From Mycoted
What is the product (ie. Multiplying all the numbers together) of the following series: (xa),(x-b),(x-c),.....(x-z)?
(A bit harder but really nothing for maths oriented minds)
Answer
Zero (0). Reasoning: any number or series of numbers multiplied by zero will equal zero.
The factor (x - x) = 0
See, we told you it was really nothing.
35
Nine Dots
From Mycoted
Imagine the pattern of dots below drawn on a sheet of paper.
Your task is to join all nine dots using only four (or less) straight lines, without lifting
your pencil from the paper and without retracing the lines.
The standard Answer
Many people who try to solve this problem start with the assumption that the lines must
be inside the square formed by the dots. But this was never stated in the original
problem!
There is always more than one right answer to many problems. Here are some other ways
you could have solved the Join the Dots problem:
Another Answer
If we had a thick pencil, we could join the dots with just three lines.
Another Answer
Why stop at three lines? Why not take a very thick pencil and do the job with just one
line???
36
Another Answer
Even with a thinner pencil, we could still make do with three lines by folding the paper
so that the dots were closer to each other.
Another Answer
If we laid the paper on the ground, we could draw one very long line which encircles the
Earth three times, joining one row of dots each time
Another Answer
And if that sounds a bit far-fetched, we could do the same thing by rolling the paper into
a cylinder.
Another Answer
Yet another solution is to fold the paper in three, so the rows of dots all line up, and fold
it again and poke the pencil through!
Another Answer
In mathematical terms, parallel lines are sometimes considered to "join" at infinity, so
here's a solution that uses just three lines!
37
Another Answer
Of course, we could question the assumption that we have to follow the rules! This
solution uses five lines ;)
Another Answer...
There are at least another 5 solutions I have come across - can you think of others.
38
Physics Problems
From Mycoted

Down in a deep coal mine, a mile or so below the surface of the earth, is the force
of gravity more or less than that at the entrance to the mine up at ground level?
(Assume the Earth has a uniform density, and ignore any centrifugal and
centripetal forces).
Answer
Down a mineshaft, the gravitational effect would be less because some of the earth's
mass is above you. That mass pulls you up, so it cancels the effect of some of the mass
below your feet that pulls you down.

A man holds a rifle horizontally 6 feet above the ground. At the moment he fires
it, another bullet is dropped from the same height, 6 feet.
Ignoring frictional effects and the curvature of the earth, which bullet hits the ground
first?
Answer
The bullets hit the ground at the same time. The rate at which the moving bullet falls is
determined by the force of gravity. This force is vertical and entirely independent of the
horizontal velocity of the projectile. Its vertical descent is the same regardless of any
horizontal velocity it may have.

Pour hot water into a thick drinking glass and into a thin wine glass. Which glass
in more likely to crack? And why?
Answer
The thick glass is most likely to crack
39

A ball, a disc and a ring, each 5 inches in diameter, sit at the top of an inclined
plane. If all three objects start rolling down the incline at the same instant, which
one will reach the bottom first? (Assume that they all roll efficiently that is, they
are perfectly formed and don't wobble--and ignore any effect of air resistance and
friction.)
Answer
The ball will reach the bottom first. Because it has less mass on the outside, and hence
less inertia.

The speed of sound in air is about 740 miles per hour. Suppose that a police car is
sounding its siren and is driving towards you at 60 miles per hour. At what speed
is the sound of the siren approaching you?
Answer
The speed of sound coming from a police siren is the same whether or not the siren is
standing still or moving.

Rupert is sailing a plastic boat in his bathtub. The boat is loaded with nuts, bolts
and washers. If Rupert dumps all these items into the water. allowing his boat to
float empty, will the water level in the bath rise or fall?
Answer
The level will fall:the metal in the boat forces the boat to sink lower in the water,
displacing water not only for the bolts, but for the air in the hull at water level. if the
bolts are allowed to sink, they displace less volume than they did in the boat(try it).

It is generally accepted that matter expands with increasing temperature, and
contracts with decreasing temperature. There is one notable exception. Which is
it, and why has nature provided for it?
Answer
Water expands below 3.98°C down to 0°C Otherwise ice would be heavier than water,
with catastrophic consequences. Lakes and ocean's would freeze from the bottom up
killing all life.
40

How could you make a raw egg float halfway between the surface and the bottom
of a glass of water?
Answer
{{{1}}}

An ice cube is floating in a beaker of water, with the entire system at 0º
Centigrade(32ºF). Just enough heat is applied to melt the ice cube without raising
the temperature of the system. What happens to the water level in the beaker?
Does it rise, fall, or stay the same?
Answer
The water level neither rises nor falls: it stays the same. The reason an ice cube floats is
because its volume has expanded during crystallisation.
41
Push that Car
From Mycoted
A man pushed his car. He stopped when he reached a hotel at which point he knew he
was bankrupt. Why?
Answer
The man pushing the car was a player in a monopoly game and his game piece was a car.
42
Quick Quiz
From Mycoted
How long did the Hundred Years War last?
Answer
116 Years
The Hundred Years' War is the name modern historians have given to what was a series
of related conflicts, fought over a 116-year period, between England and France, and
later Burgundy; beginning in 1337, and ending in 1453. Historians group these conflicts
under the same label, for convenience.
Which country makes Panama hats?
Answer
Ecuador
Despite the name, genuine Panama hats are made in Ecuador, not Panama; their naming
comes from the fact that they came to prominence during the construction of the Panama
Canal.
From which animal do we get catgut?
Answer
sheep or goat Catgut is the name applied to cord of great toughness and tenacity
prepared from the intestines of sheep/goat, or occasionally from those of the hog, horse,
mule, and donkey. Those of the cat are not employed, and therefore it is supposed that
the word is properly kitgut "violin string", kit meaning "fiddle", and that the present
form has arisen through confusion with kit = cat.
In which month do Russians celebrate the October Revolution?
Answer
November
November 7, to be exact. The original Russian (Julian) calendar was 13 days behind
ours. It is also known as the Bolshevik Revolution and led to the creation of the Soviet
Union in 1917.
43
What is a camel's hair brush made of?
Answer
Paintbrush bristles described by manufacturers as camel hair are actually derived either
from the hairs of horses, squirrels, goats, sheep, bears, or some combination of these.
What was King George VI's first name?
Answer
Albert
The Canary Islands in the Pacific are named after what animal?
Answer
Dogs
In Latin, they were "Insularia Canaria"--Islands of the Dogs.
What color is a purple finch?
Answer
Raspberry red / crimson
Where are Chinese gooseberries from?
Answer
New Zealand
A New Zealand horticulturalist developed the kiwi from the original Chinese plant.
Which seabird has the zoological name Puffinus puffinus?
Answer
Manx Shearwater
From which material are mole-skin trousers made?
Answer
Cotton, it is a heavy-napped cotton twill fabric, and not really from moles
Louis the XVIII (18th) was the most recent king of France, but how many previous kings
of France were called Louis?
44
Answer
16
Louis XVII (17th), Prince Royal of France, was the son of King Louis XVI of France
and Marie Antoinette. He never reigned as King of France.
How long did the Thirty Years War last?
Answer
30 years.
Well, there had to be one without a catch ;)
45
Sheep
From Mycoted
Is it correct to say;
"The herd of sheep is eating hay in the field"
or
"The herd of sheep are eating hay in the field"?
Answer
Neither - the collective noun for sheep is a flock of sheep - not a herd of sheep.
46
Sheep Pens
From Mycoted
A Farmer has twelve sheep and decides to put each of them into a separate pen; but to
make the pens he has only 12 long hurdles and 6 half length hurdles. How can he do it?
Answer
The farmer needs to arrange the 12 long hurdles in the shape of a hexagon made of 6
triangles, and then use the six short hurdles to divide each triangle into two.
Alan Butler spotted a solution which left a spare hurdle - can anyone improve on this?
Tim Bray spotted a solution which had 4 spare hurdles, although I suspect he might have
47
cut the hurdles!!!!
Following my comments suggesting he may have cut some of the hurdles, Tim has come
up with a couple of other solutions, which certainly don't need a saw.
This one uses 11 long and 6 short, leaving one spare long hurdle
This one uses 12 long and 4 short, leaving two spare hurdles.
48
Straight Lines
From Mycoted
Are the two horizontal lines straight or curved?
Answer
Both horizontal lines are straight.
Sometimes it is difficult to see the wood for the trees, and 'information' around the object
or problem you are interested in can distort your view. Try covering the lines with a
piece of card, or when looking at a problem try and remove some of the 'non-relevant
information'.
49
Summer Months
From Mycoted
What occurs once in June, once in July and twice in August?
Answer
The letter U.
50
The Arm of the Postal Service
From Mycoted
One day a man received a parcel in the post. Carefully packed inside was a human arm.
He examined it, repacked it and then sent it on to another man. The second man also
carefully examined the arm before taking it to the woods and burying it. Why did they do
this?
Answer
The three men had been stranded on a desert island. Desperate for food, they had agreed
to amputate their left arms in order to eat them. They swore an oath that each would have
his left arm cut off. One of them was a doctor and he cut the arms off his two
companions. They were then rescued. But his oath was still binding so he later had to
have his arm amputated and sent to his colleagues. This is often told with a further twist
whereby a doctor pays a tramp a large sum in order to amputate the tramp's arm which
the doctor then sends to another man who inspects it etc. This variation can make for a
long night of questioning!
51
The Blind Beggar
From Mycoted
A blind beggar had a brother who died. What relation was the blind beggar to the brother
who died? (Brother is not the answer)
Answer
The blind beggar was the sister of her brother who died. This puzzle is one of a type that
depends on the listener making implicit assumptions about gender - in this case that a
blind beggar is a man. Similar puzzles involve surgeons who refuse to operate on their
sons etc. This is probably the best of the class because it is very simply stated and yet
which has the power to baffle those who have not heard it before.
52
The Broken Match
From Mycoted
A man is found dead in a field. He is clutching a broken match. What happened?
Answer
He and a number of other passengers were making a balloon trip in a desperate attempt
to flee a country. The balloon had to lose weight to stop it from crashing. He drew the
short match and had to jump
53
The Coal, Carrot and Scarf
From Mycoted
Five pieces of coal, a carrot and a scarf are lying on the lawn. Nobody put them on the
lawn but there is a perfectly logical reason why they should be there. What is it?
Answer
They were used by children who made a snowman. The snow has now melted.
54
The Deadly Dish
From Mycoted
Two men went into a restaurant. They both ordered the same dish from the menu. After
they tasted it, one of the men went outside the restaurant and shot himself. Why?
Answer
The dish that the two men ordered was albatross. They had been stranded many years
earlier on a desert island. When the man tasted albatross he realised that he had never
tasted it before. This meant that the meat he had been given on the island was not
albatross as he had been told. He correctly deduced that he had eaten the flesh of his son
who had died when they first reached the island. This has something in common with
The Arm of the Postal Service but is in my opinion even better. It is fiendishly difficult
to figure out from a standing start. A beautiful aspect of this problem is the subtle fact
that he shot himself because he did not recognise the taste of the dish!
55
The Deadly Party
From Mycoted
A man went to a party and drank some of the punch. He then left early. Everyone else at
the party who drank the punch subsequently died of poisoning. Why did the man not die?
Hint
He drank as much punch as those who drank it later and died ....
The poison had been in the punch bowl all the time ....
Answer
The poison in the punch came from the ice cubes. When the man drank the punch the ice
was fully frozen. Gradually it melted, poisoning the punch.
56
The Elder Twin
From Mycoted
One day Kerry celebrated her birthday. Two days later her older twin brother, Terry,
celebrated his birthday. How come?
Answer
At the time she went into labour, the mother of the twins was traveling by boat. The
older twin, Terry, was born first early on March 1st. The boat then crossed the
International Date line (or any time zone line) and Kerry, the younger twin, was born on
February the 28th. In a leap year the younger twin celebrates her birthday two days
before her older brother.
57
The Man in the Bar
From Mycoted
A man walks into a bar and asks the barman for a glass of water. The barman pulls out a
gun and points it at the man. The man says 'Thank you' and walks out.
Answer
The man had hiccups. The barman recognised this from his speech and drew the gun in
order to give him a shock. It worked and cured the hiccups - so the man no longer
needed the water.
This puzzle has claims to be the best of the genre. It is simple in its statement, absolutely
baffling and yet with a completely satisfying solution. Most people struggle very hard to
solve this one yet they like the answer when they hear it or have the satisfaction of
figuring it out.
It is a simple puzzle to state but a difficult one to solve. It is a perfect example of a
seemingly irrational and incongruous situation having a simple and complete
explanation. Amazingly this classic puzzle seems to work in different cultures and
languages.
58
The Man who Hanged Himself
From Mycoted
Not far from Madrid, there is a large wooden barn. The barn is completely empty except
for a dead man hanging from the middle of the central rafter. The rope around his neck is
ten feet long and his feet are three feet off the ground. The nearest wall is 20 feet away
from the man. It is not possible to climb up the walls or along the rafters. The man
hanged himself. How did he do it?
Answer
He climbed on a block of ice which has since melted.
This one is often stated with the clue of a puddle of water, but surely this is too much
assistance. It is one of several problems which depend on the change of state of water
(snow or ice to water or steam).
An alternative solution is that he climbed the rope, then put the end of the rope around
his neck and let go.
Many thanks to Bob Kew for another intriguing solution: He used a bale of hay to stand
on, or jump off, which has been eaten by sheep (which have left).
59
The Music Stopped
From Mycoted
The music stopped. She died. Explain.
Answer
She was a circus tight-rope walker who walked blindfolded over a high wire. The band
played as she crossed and when the music stopped it was the signal that she had reached
the end of the walk and could safely alight. One day the conductor was taken ill and the
stand-in conductor ended the piece of music too early. She stepped off to her death.
60
The Realisation
From Mycoted
A man was walking downstairs in a building when he suddenly realised that his wife had
just died. How?
Answer
The man had visited his wife in hospital. She was on a life-support machine. As he was
walking down the stairs all the lights went out. There had been a power cut and the
emergency back-up systems had failed. He knew that she had died.
Alternative: The man's wife was suffering from depression. She was also suicidal. When
he was getting down the stairs,she had jumped out and he saw her falling
61
The Royal Mint
From Mycoted
You are the treasurer in charge of the Royal mint, which produces a single type coin, the
grote. There are ten machines producing grotes, one machine is producing grotes
weighing one gram less than they should, each coin should weigh 10 grams. You have a
set of broken scales which can be fixed to provide one single weigh of a single amount
(no weight changes are allowed). Using the scales once you must identify the single
faulty machine.
How do you do it?
Answer
Label the machines 1 thru to 10, take one coin from machine 1, 2 from machine 2 etc.
However many grams you are out from you calculated total is the number of the
machine producing the substandard coins.
62
The Swimmer in the Forest
From Mycoted
Deep in the forest was found the body of a man who was wearing only swimming trunks,
snorkel and facemask. The nearest lake was 8 miles away and the sea was 100 miles
away. How had he died?
This is supposedly based on a true incident. Does this make it an urban legend? Many
urban legends can be restated as lateral thinking puzzles.
Answer
During a forest fire, a fire-fighting plane had scooped up some water from the lake to
drop on the fire. The plane had accidentally picked up the unfortunate swimmer.
63
The bird and the cars
From Mycoted
Consider a road with two cars, at a distance of 100 kilometres, driving towards each
other. The left car drives at a speed of forty kilometers per hour and the right car at a
speed of sixty kilometers per hour. A bird starts at the same location as the right car and
flies at a speed of 80 kilometers per hour. When it reaches the left car it turns its
direction, and when it reaches the right car it turns its direction again to the opposite,
etcetera.
The Question: What is the total distance that the bird has traveled at the moment that the
two cars have reached each other?
Answer
If you have written down a whole page full of mathematical formulae, then you have
probably been thinking in the wrong direction for this puzzle. The two cars will meet
each other after one hour, hence the bird has been flying for one hour.
The bird has flown 80km when the cars meet.
64
The man in the Elevator
From Mycoted
A man lives on the tenth floor of a building. Every day he takes the elevator to go down
to the ground floor to go to work or to go shopping. When he returns he takes the elevator
to the seventh floor and walks up the stairs to reach his apartment on the tenth floor. He
hates walking so why does he do it?
Answer
The man is too short to reach the number 10 button.
An alternative solution: The elevator only runs to the 7th floor. The riddle did not state
that he takes the elevator from the 10th floor in the morning, just that he takes the
elevator to the ground floor. He walks to the 7th floor each morning to take the elevator
to the ground floor also.
65
There are many correct ways to answer a
test question
From Mycoted
R.L. Loeffelbein, a physics teacher at Washington University in St. Louis was about to
give a student a zero for the student's answer to an examination problem. The student
claimed he should receive a perfect score, if the system were not so set up against the
student. Instructor and student agreed to submit to an impartial arbiter, Dr. Alexander
Calandra, who tells the story.
The examination problem was: "Show how it is possible to determine the height of a tall
building with the aid of a barometer."
The student's answer was, "Take the barometer to the top of the building, attach a long
rope to it, and lower the barometer to the ground. Then, bring it back up, measuring the
length of the rope and barometer. The lengths of the two together is the height of the
building."
I, as arbiter, pointed out that the student really had a strong case for full credit since he
had answered the problem completely and correctly. On the other hand, of course, full
credit would contribute to a high grade for the student in his physics course, and a high
grade is supposed to certify that the student knows some physics, a fact that his answer
had not confirmed. So it was suggested that the student have another try at answering the
problem.
He was given six minutes to answer it, with the warning this time that the answer should
indicate some knowledge of physics. At the end of five minutes, he had not written
anything. Asked if he wished to give up, he said no, that he had several answers and he
was just trying to think which would be the best. In the next minute he dashed off this
answer. "Take the barometer to the top of the building. Lean over the edge of the roof,
drop the barometer, timing its fall with a stopwatch. Then, using the formula S=½at2,
calculate the height of the building.
At this point, I asked my colleague if he gave up and he conceded. The student got nearly
full credit.
Recalling that the student had said he had other answers, I asked him what they were.
"Well," he said, "you could take the barometer out on a sunny day and measure the height
of the barometer, the length of its shadow, and length of the building's shadow, then use
simple proportion to determine the height of the building. And there is a very basic
66
measurement method you might like. You take the barometer and begin to walk up the
stairs. As you climb, you mark off lengths of the barometer along the wall. You then
count the number of marks to get the height of the building in barometer units.
"Of course, if you want a more sophisticated method, you can tie the barometer to the end
of a string, swing it as a pendulum, and determine the value of 'g.' The height of the
building can, in principle, be calculated from this.
"And," he concluded, "if you don't limit me to physics solutions, you can take the
barometer to the basement and knock on the superintendent's door. When he answers,
you say, 'Mr. Superintendent, I have here a fine barometer. If you will tell me the height
of this building, I will give you this barometer.'"
Finally, he admitted that he even knew the correct textbook answer -- measuring the air
pressure at the bottom and top of the building and applying the appropriate formula
(p=p0e-ay) illustrating that pressure reduces as height increases -- but that he was so fed up
with college instructors trying to teach him how to think instead of showing the structure
of the subject matter, that he had decided to rebel.
For my part, I seriously considered changing my grade to unequivocal full credit.
R.L. Loeffelbein has been a teacher and writer for 20 years. He was an assistant professor
aboard the first voyage of the University of the Seven Seas.
67
Three Men at a Hotel
From Mycoted
Hercules, Santa Claus and Prince Charming enter a hotel and pay the confused manager
$30 for a room($10 for each man). Later, the manager realises he has overcharged them
and gives $5 to the bellboy to return to the men. As the bellboy walks up the stairs of the
surprisingly cheap hotel, he ponders that the $5 note won't easily divide by three between
the men and definately doesn't wish to start some money fight between such important
people. When he knocks on their door he ends up handing them just $3 in coins, keeping
$2 on the sly.
The men have now paid $27 for the room and the bellboy has $2. Where is the final
dollar?
Caution: Many people say "there is no missing dollar" - but unless you can explain why,
without confusing yourself, your answer should be considered wrong.
Answer
This is a puzzle based off confusing people by putting them in a logically illegal
situation and forcing them to try to make sense of it. Solving it requires backtracking to
the logic error and rejecting it. Naturally, there is no missing dollar, so what is
happening?
The men paid $27, of which the bellboy has $2 and the hotel manager has $25. 27 = 2 +
25.
You could try doing 27 + 2 = 29, but it produces a non-meaningful result. (What does
that $29 represent?) You've added the same $2 twice over(which is wrong). If it is so
important to add things to $30, then go with the sum of 25 + 2 + 3 = 30, representing the
amount of money that each group of people now have.
The point of this problem is to confuse people - if your math isn't hot, you're probably
still confused.
Those with active math usage, like accountants, won't even understand how this can be
considered a puzzle.
68
Triangle Ratios
From Mycoted
A circle has an equilateral triangle touching it's circumference on the outside and another
equilateral triangle touching its circumference on the inside, as pictured. What is the ratio
of the areas of these two triangles?
Answer
You don't need to do any complicated maths, if you rotate the inner triangle by 180
degrees it should become obviously guickly that the ratio is 1:4.
69
Trouble with Sons
From Mycoted
A woman had two sons who were born on the same hour of the same day of the same
year. But they were not twins. How could this be so?
Answer
They were two of a set of triplets (or quadruplets etc.) This simple little puzzle stumps
many people. They try outlandish solutions involving test-tube babies or surrogate
mothers. Why does the brain search for complex solutions when there is a much simpler
one available?
70
Wetter as it Dries
From Mycoted
What gets wetter as it dries?
Answer
A towel.
71
What is it...
From Mycoted
The man who sold it did not want it.
The man who bought it did not need it.
The man who used it did not know it.
What is it?
Answer
A coffin.