THINGS YOU CAN EXPECT TO
1. MORE
2. LINKS TO ANSWERS TO
I'LL DO THAT SOON....
TILL THEN, HAPPY SOLVING ...
Happy Solving
Puzzle 1:
Square and Cockroaches
Puzzle 2 :
Ages and weights
Puzzle 3 :
Color of Eyes
Puzzle 4 :
Puzzling mixture
Puzzle 5 ;
13 balls and a weighing balance
Puzzle 6 :
True lies
Puzzle 7 :
Hare tortoise paradox
Puzzle 8 :
Newton and Einstien
Puzzle 9 :
Weighing balance once again
Puzzle 11 :
Weighing balace once again once again
Puzzle 12 :
Fruits and coins
Puzzle 13 :
The Cannibal's Puzzle
Puzzle 14 :
The Cannibal's Second Puzzle
Puzzle 15 :
The Ten Coin Bags
Puzzle 16 :
A Problem with Ages
Puzzle 17 :
Apples and Lemons
Puzzle 18 :
The Grammar Game
Puzzle 19 :
Satellites
Puzzle 20 :
A Strange Tower
Puzzle 21 :
Spring balance and 4 coins
Puzzle 22 :
Ghost at the table
Puzzle 24 :
An efficient car
Puzzle 25 :
Paradox again
Puzzle 26 :
Tiles
Puzzle 27 :
Logicians' test
Puzzle 28 :
Logicians' test II
Puzzle 29 :
Piece of cake
Puzzle 30 :
LATERAL THINKING - (not a puzzle)
Puzzle 31 :
Hungry lion
Puzzle 32 :
what next ?
Puzzle 33 : Odd number out
Puzzle 34 :
Probability
Puzzle 35 :
Who owns the zebra ?
Puzzle 36 :
Milk Jars
Puzzle 37 :
Hourglass twister
Puzzle 38 :
5 queen problem
Puzzle 39 :
8 queen problem
Puzzle 40 :
Stuck in the desert
Puzzle 41 :
Cool puzzle
Puzzle 42 :
Round trip
Puzzle 43 :
Two spheres
Puzzle 44 :
Box with the gold
Puzzle 45 :
Can smuggler escape ?
Puzzle 46 : Arrange points in rows
Puzzle 47 :
Poor dog
Puzzle 48 :
"C" Programming puzzle
Puzzle 49 :
Imitation gummy bears
Puzzle 50 :
How can this be true ?
Puzzle 51 :
High school geometry
Puzzle 52 :
A farmer with a rectangular farm
Puzzle 53 :
2 fingers - 2 coins
Puzzle 54 :
Prison with 100 cells
Puzzle 55 :
Hands of a clock
Puzzle 56 :
Alphabets
Puzzle 57 :
Distribution of money
Puzzle 58 :
Rope puzzle
Puzzle 59 :
Lonely 7
Puzzle 60 :
C - Linked list puzzle
Puzzle 61 :
Pirates !!!
Puzzle 62 :
Restaurant
Puzzle 63 :
Move a stick
Puzzle 64 :
Self referencing number
Puzzle 65 :
Time management
Puzzle 66 :
Train Car and a walking man
Puzzle 67 :
Pune Mumbai shuttle
Puzzle 68 :
Avarage speed
Puzzle 69 :
Magnet
Puzzle 70:
Bridge and a lamp
Puzzle 71:
Clock Hands
Puzzle 72:
Brick
Puzzle 73:
Descriptor Series
Puzzle 74:
Time measuring ropes
Puzzle 75 : 9 digit number
Puzzle 77 :
BABY
Puzzle 78 :
Powers
Puzzle 79 :
Card Trick
Puzzle 80 :
River crossing
Puzzle 81 :
Water from river
Puzzle 82 :
Grid and dot
Puzzle 83 :
Stream of Integers
Puzzle 84 :
Now or Never!
Puzzle 85 :
LCM and GCD
Puzzle 86 :
Special Triangle I
Puzzle 87 :
Special Triangle II
Puzzle 88 :
Amoebae
Puzzle 89 :
Coins
Puzzle 90 :
Sum and difference
Puzzle 91 :
Coin weights
Puzzle 92 :
Couple Handshakes
Puzzle 93 :
Handshakes II
Puzzle 94 :
2 Million points
Puzzle 95: Horse
Race I
Puzzle 96 : Horse Race II
Puzzle 97 : Squint
man
Puzzle 98 : Hungry lion
Puzzle 99 : Boy or girl ?
******************************
PUZZLE 1
******************************
There's a
square of 10m x 10m. At the beginning of this puzzle, there are 4 cockroaches
at the four corners of this square. Now EACH COCKROACH starts walking towards
the cockroach which is on the adjacent corner of the square. ( Everybody tries to approach the creature which is on right
side - say i.e. no creature tries to approach the one which is coming towards
it.- I hope you got my point) So everybody starts walking
towards a destination which itself is not fixed. Interesting situation
isn't it ??
Suppose
the speed of walking of cockroaches is 1 meter/min. What will happen ?? will they meet ??
After how much time will they meet ??
***************************
PUZZLE 2
***************************
Here is a
conversation between two friends A and B who meet after a long time.
A: I have three daughters. Identify their ages.
B: Hey, you have to give me some clue yaar, how can I directly Identify their ages from this information ??
A: Ok, Sum of their ages is 13.
B: ......( thinks ) No.
still I can't.
A: Ok, Product of their ages is equal to your age.
B: ......(thinks) No. still
I can't.
A: Ok, my eldest daughter weighs 30 kg.
B: Yeh hui
na baat !! I got it.
Yes and he
really gets it. Now can you identify their ages ????
***************************
***************************
In this particular tribe, having one's eyes
"blue" is considered the most evil thing. One
who gets to know (finds out) that his eyes are blue, commits suicide on the
very same
But they don't have mirrors there. (and water does not reflect light properly, and they don't
have metal utensils etc.), so one can't know the color of his eyes that way.
There are in all 48 blue eyed and 49 black eyed intelligent men in the tribe.
Every day all the men in the tribe assemble for
the lunch, but they do not tell each other wheather
he is blue eyed or not. There is absolutely no
communication between them. (Of course they look at
each other's faces and notice color of his eyes)
One day one scientist (probably the same one as in the horn's puzzle) visits this tribes and tells them that there is at least one blue eyed man in the tribe.
What would be the effect of this
? i.e. Would anybody kill himself ? Who ? when ? how
? why ? etc.
***************************
***************************
This is simple but still interesting one.
I have 2 cups ( may not be
identical ). One cup (water cup)contains some quantity
of water in it and other ( alcohol cup) contains some quantity of alcohol in
it. For the sake of puzzling you, I did this :
1. Took 1 spoon of water from water cup and added it
to alcohol cup and stirred thoroughly.
2. Took 3 spoons full of liquid from alcohol cup and
added to water in water cup and stirred again.
3. Took 4 spoons of mixture from water cup and added
to alcohol cup and of course stirred the mixture.
4. Took 2 spoons of liquid from alcohol cup and
added it to liquid in water cup and stirred it.
Got bored ?? Ok. This is all that I did.
This created a mixture of water and alcohol in both
the cups
Now the question is, more water goes into alcohol of alcohol cup or more alcohol goes into water of
water cup ??
HINT : This is a puzzle. not maths problem
***************************
***************************
Here is today's
puzzle. A difficult one but very popular so you may have solved it or may be knowing the answer. It goes like this.
I have 13
metal balls. They are identical as far as their external features ( radius, color,lustur etc.) is
concerned. But one of the balls is defective . Defective in the sense that its weight is different than the
remaining balls. ( heavy or light - nobody
knows.).
I am
given a weighing balance with no weights. How can I locate the defective ball
from the rest of the balls in the lot; just by using the balance THRICE ?? ( I am not allowed to use
the balance more than three times . Why ??? That is
not the part of this puzzle)
************************************
For
those who know the answer, here is the extension of the puzzle
:
If I am
allowed to use the balance 5 times. In that case, out of how many balls, can I
locate the defective ball ???
***************************
***************************
You are trapped
in a room having 2 doors. You know that one door leads to death and other to
life. Each door is guarded by one guard. Everybody knows that one of the guard always lies while the other always tells the truth.
You don't know who lies and who tells the truth.
Ask only
one question to a guard on any of the door and decide which door will lead to life ???
You know the answer ??
But there is one more. Try to find that also.
***************************
***************************
Simple situation :
I have a rubber ball. It has a property that when you drop it from a certain
height, it bounces back to half the height. I drop it from a height of 10 mtrs.
Simple questions:
1. How
many times it will bounce ??
2. For how
much time will it bounce ???
( you may assume ball to be a point mass and its
property of bouncing to half the height is independent of the value of the
height )
***************************
PUZZLE 8
***************************
There are 2
whole numbers between 3 and 99, both included.
i.e.. 2 integers belong to
the closed interval [3,99]. Everybody
knows about the existence of these numbers, but not
what the numbers,
themselves are. Also, anybody knowing one or both of these numbers,
immediately declares knowledge of these numbers. i.e. they say they
know the numbers but don't actually reveal the
numbers.
Einstien knows the sum of the numbers while
product of the numbers. Once the two of them meet
and the following
dialogue goes:
E: I know the sum
of the numbers
N: I know the product
of the numbers
E: I don't know the
numbers
N: I knew you would'nt know the numbers
E: Now I know the
numbers
N: Now I also know the
numbers.
What are the numbers?
Note: Please do not regard the second
statements of Einstein and
would anyway reveal that they know it.
***************************
***************************
I have a set of
N metal balls which look identical. Out of these N balls, 1 ball is defective(its mass is different than the rest). I don't know
whether it's heavy or light.
I have a
weighing balance but no weights. I am given 6 chances to use the weighing
balance, to detect the defective ball.
What can
be the maximum value of N so that I can pinpoint the defective ball out of them ??? and how ????
***************************
***************************
Given 21 coins, one of which weighs slightly more
than the others, and a two-plate scale, how many
weightings are necessary to determine the heavier coin?
What if there are 200 coins, among which there is
again one coin slightly heavier than the others. How
many weightings are necessary now?
Finally, given n coins and a two-plate scale, how
many weightings are necessary to find the heavier
coin?
***************************
***************************
Peter is playing around with a two-plate scale and
finds that the scale stays in equilibrium if one plate
is filled with two keys, two coins and three toy
soldiers OR one apple, one toy soldier and one lemon,
and the other plate with a weight of 100g.
One coin, one key, one soldier and one plum together
weigh 50g. The lemon, the apple and the plum
weigh exactly the same as one coin, one key, one
soldier and one condom.
How much weighs the condom?
***************************
***************************
The Cannibal's Puzzle
While exploring the jungle three scientists get
caught by a tribe of cannibals. Begging for mercy, they
finally are granted one last chance to save their
lives: Each of them is bound to a stake, so that one
scientist can see the backs of the other two before
him, the one in the middle can only see the back of
the one in front, while the latter can't see
anybody. They are now shown five colored feathers, among
which there are three white ones and two black ones.
They are then blindfolded and each of them is put
one of the feathers into his hair. Finally they are
taken off the blindfolds and posed the question to
determine the color of their own feathers. If only
one of them should be able to guess the correct color,
all three of them would be released.
Time passes... then the man bound to the foremost
stake (who actually can't see anybody) correctly
names the color of his own feather. What thoughts
must have lead to his answer?
***************************
***************************
The Cannibal's Second Puzzle
The preassumptions are
just as detailed in "The Cannibal's Puzzle", but this time the three
men are
allowed to wander around and look at each other.
Again it's only several minutes before the first man
tries to guess the color of his feather... he is, of
course, correct. How could he determine the color and
what color was it?
***************************
***************************
The Ten Coin Bags
On the table in front of you you
can see ten bags filled with ten coins each, but the coins in one of the
bags are all fakes. The only thing known about a
fake coin is the fact that its weight differs by exactly
one gram from the weight of a valid coin (which is
an integer number greater than 0), but not whether
it is heavier or not. You are allowed to use a twoplate scale which gives the weight in grams. If
you're only allowed to use this scale ONCE, how
would you try to find the bag with the fake coins?
***************************
***************************
A Problem with Ages
Two logicians meet and while chatting their talk
also leads to their families. Questioned for the ages
of his three children one of them answers: "The product of the ages
of my three children is 72." The
other logician thinks for a moment and then states
that this is not enough information. The first man
therefore says: "Well, have
a look at the building number outside the entrance door... that's the sum of
their ages." This having done the other one
comes back shaking his head... "I still don't know...".
"Alright", the first man says, "I'll
give you one more hint: my youngest child is named Ann."
How old are the three children?
***************************
***************************
Apples and Lemons
In the garage behind his house, Bill keeps three
big boxes. One of the boxes is labeled "Apples",
another one "Lemons" and the last one
"Apples and Lemons". The only thing Bill knows is that none
of the labels is correct! How could Bill correctly
re-label all the boxes, if he is only allowed to take
out
***************************
***************************
The Grammar Game
You can make the following into grammatically
correct English merely by adding punctuation. You may
not change the word order, nor add or subtract any
words.
John while Jim had had had
had had had
had had had
had had a better effect on
the teacher
***************************
***************************
How many satellites are needed to see the entire
earth surface at...
A) a given moment
B) continuously, when satellites are in free-fall
orbit (around
the earth, neglecting sun, moon etc.)
***************************
***************************
A Strange Tower
You are given a heap of domino tiles and
challenged with the following problem: Can you pile up the
stones so that the topmost tile stands out for more
than his entire length compared to the lowermost
tile?
For mathematicians: Given an infinite number of
tiles, how many times his own length can you make
the topmost tile stand out of the tower? Proof your
statement!
***************************
***************************
You have got a spring balance and three coins.
Faulty coin weighs 9g and a
proper one weighs 10g. In how many weightings one
would know which coins are
faulty ?
***************************
***************************
There is
a square table. There are 4 glasses kept at the four corners of the table. The
orientation of glasses (one or more) can be normal or inverted (like \/ this or
like /\ this ). Your eyes are tied. You are standing
near one of the sides of the table. You are allowed to touch any two glasses at
a time ( any two of any of the sides or any of the
diagonals) You can feel them and you can change their orientation as per your
wish.
The aim
is to have same orientation of all the glasses. (normal
or inverted).
There is
a problem :
There is
a ghost. It turns the table after each of your move(in
multiples of 90 degrees). So, You done know which side
is there in front of you.
How can
you fulfil your aim.
Note :.
1. There is an alarm which goes when all glasses
have same orientation (otherwise you won't know that the task is done)
2. HINT : You can do it -
POSITIVELY - no probability issue..
***************************
***************************
I have a car.
Its fuel consumption is 1 lit/km.
The fuel tank of the car has capacity of 500 liters. I can't
carry with me any fuel other than that stored in the tank .
My
destination is 1000 km. from the starting point.
At the
starting point, there is a petrol pump with infinite storage capacity.
There are
no petrol pumps anywhere else.
I can
store any amount of fuel anywhere near the side of the road and can use it
later. But that fuel has to be carried to that point in the fuel tank of the
car.
The rate
of evaporation of fuel is exactly 0.000 lit/hour
How
should I plan my journey so that least amount of fuel is consumed
???
***************************
***************************
1. I have a rubber ball. It bounces in such a
way that each bounce of it; has 75% the amplitude as
compared to the amplitude of the previous bounce. so
if it is thrown from 100 meters it will rise upto 75
meters.
Initially
the ball is thrown from 60 meters.
Q1. How
many times will it bounce ??
Q2. For
how much time will it bounce ??
2. I have a pendulum. It oscillates in such a way
that each oscillation of it; has 75% the amplitude as compared to the amplitude
of the previous oscillation. So, if nth
oscillation has magnitude 100 degrees, n+1 th will
have 75 degrees.
Initially
the pendulum is given amplitude equal to 60 degrees.
Q1. How
many oscillations will take place ??
Q2. For
how much time will it oscillate ??
3. A car is revolving in a circular path. Its
speed reduces to 75% of its previous speed after completion of each revolution.
Initially
car is moving at a speed of 60 m/s
Q1. How
many revolutions
***************************
***************************
Here is a
puzzle carrying Prize tag of 2 Samrat Coupons.
Size
of 1 tile is 1 foot by 1 foot.
63*81 (=
5103) such tiles cover a big rectangular
region.
Length of this rectangular region is 81 feet
and width
is 63 feet.
If a
diagonal of this rectangle is drawn, how many tiles
will it cut ??
The first
correct and "elegant" answer gets the prize
***************************
***************************
The moderator takes a set of 8 stamps, 4 red and 4
green, known to the
logicians, and loosely affixes two to
the forehead of each logician so that each logician
can see all the other
stamps except those 2 in the
moderator's pocket and the two on her own head. He
asks them in turn if they
know the colors of their own
stamps: A: "No" B: "No" C:
"No" A: "No B: "Yes" What are the colors of her
stamps, and what is the
situation?
***************************
***************************
Here is an interesting problem.
Once upon a time there was a wise, just and
bright king who summoned all the famous
mathematicians of his country to his court. They
were twenty in all. He had all of them
sent to a big room , had
them blindfolded and had some black and some white caps placed on
their bald and intelligent heads. Then he had
the blind folds removed and told them he
had placed some black and some white hats on
their heads . He ordered them not to utter
a word to one another and that he had hidden cameras
and microphones in the room to ensure
they did not communicate in any way. He said he
would return to the room every hour on the
hour and that when he did so, those mathematicians
who knew they had white hats could go out
with him. Those who wrongly left would ofcourse be done to death.
There were actually nine white hats. Did the
mathematicians ever find out what hat they
were wearing? If they did, how many times did the
king have to visit them by the time they
found out.
Assume all the mathematicians were really
smart and were brave enough to leave if they knew.
Note that the guys don't know how many
white/black hats were there
***************************
***************************
You have
arranged a party,and you
realize that more people have turned up than
you expected.In the end you are left with 1 big piece of cake.You have a knife
but you
are allowed to take only 4 (linear) cuts with it.
Maximum no. of pieces possible.???
How would
you cut the cake to have max. no.
of pieces??
***************************
***************************
<LATERAL THINKING>
1. The maker doesn't want it; the buyer
doesn't use it; and the
user doesn't
see it. What is it?
2. A child is born in
both born in
citizen. How is this possible?
3. Before
mountain on Earth?
4. Clara Clatter was born on December 27th,
yet her birthday is
always in the summer. How is this possible?
5. Captain Frank and some of the boys were
exchanging old war
stories. Art Bragg offered one about how
his grandfather led a
battalion against a
German division during World War I. Through
brilliant maneuvers he defeated them
and captured valuable
territory. After the battle he was
presented with a sword bearing
the inscription "To Captain Bragg
for Bravery, Daring and
Leadership. World War I.
From the Men of Battalion 8."Captain Frank
looked at Art and said, "You really don't expect anyone to believe
that yarn, do you?" What's wrong with the
story?
6. What is one thing that all wise men,
regardless of their
religion or politics, agreed is between heaven
and earth?
7. In what year did Christmas and New
Year's fall in the same
year?
8. A woman from
city, yet she did not break any laws. None of
these men died and she
never divorced. How was this possible?
9. Why are 1990 American dollar bills worth
more than 1989
American dollar bills?
10. How many times can you subtract the
number 5 from 25?
11. How could you rearrange the letters in
the words "new door"
to make one word? Note: There is only one
correct answer.
12. Even if they are starving, natives
living in the
never eat a penguin's
egg. Why not?
13. Which is correct to say, "The yolk of the egg are white" or
"The yolk of the egg is white"?
.
14. In
with a wooden leg. Why not?
15. There were an electrician and a plumber
waiting in line for
admission to the "International Home
Show". One of them was the
father of the other's son. How could this be
possible?
16. After the new Canon Law that took
effect on
1983
sister?
The Answers
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
1. a coffin
2. the child was born
before 1776
3.
4. Clara lives in the
southern hemisphere.
5. World War I wasn't called "World War
I" until World War II.
6.The word
"and".
7. They fall in the same year every year, New
Year's Day just
arrives very early in the year and Christmas
arrives very late in
the same year.
8. The lady was a Justice of the Peace.
9. One thousand nine hundred and ninety dollar
bills are worth
one dollar more than one thousand nine hundred
and eighty-
nine dollar bills.
10. Only once, then you are subtracting it
from 20.
11. "one
word"
12. Penguins live in the Antarctic.
13. Neither, the yolk of the egg is yellow.
14. You have to take a picture of a man with a
camera, not with
a wooden leg.
15. They were husband and wife.
16. He can't because he's dead.
***************************
***************************
An antelope is at the center of a circular
lake. The antelope can
swim at the speed of 1 mile/hr. The lake has a
radius of 1 mile.
At the bank of the lake there is a lion. The lion
can run at a speed
of 4 miles/hour. Once the antelope reaches the
ground it can outrun
the lion and save itself. But if the lion has
already reached the
point where the antelope reaches the ground then the
lion eats the
antelope.
Does the antelope have a chance to get out
alive? how?
***************************
***************************
What is the next number in this
series?
1
1 1
2 1
1 2 1 1
1 1 1 2 2
1
3 1 2 2 1 1
1 3 1 1 2 2 2 1
***************************
***************************
Which is the odd man out in this series ?
111, 131, 242, 263, 284, 331, 482, 551
***************************
***************************
Two non negative numbers are
chosen at random. What is
the probability that their sum is
divisible by ten?
***************************
***************************
There are five houses.
Each house is a unique
color.
Each house owner is a
different nationality. Each house owner has a
different pet.
Each house owner drinks a
different drink. Each house owner smokes a
different cigarette. The
Englishman lives in the red house.
The Swede has a dog.
The Dane drinks tea.
The green house is on the
left side of the white house. In the green
house they drink coffee.
The man who smokes
Dunhill. In the middle
house they drink milk.
The Norwegian lives in the
first house.
The man
who smokes Blend, lives in the house next to the house with
cats.
In the house next to the
house where they have horses, they smoke
Dunhill.
The man
who smokes Blue Master, drinks beer. The German smokes Prince.
The Norwegian lives next to
the blue house.
They drink water in the
house that lays next to the house where they
smoke Blend.
Question: Who owns the
Zebra?
***************************
***************************
7 Lt jar, 13 Lt jar
& a 19 Lt jar.
There are 19 Lts of Milk
in the 19 Lt jar and 1 Lt in the 7 Lt jar.
Now all u have to do is separate out 10 lts of milk in the 13 & 19 lt
jars
respectively.
U have to use these jars
alone to achieve this.
***************************
***************************
You are a cook in a remote area with no clocks or
other way of
keeping time other than a four minute hourglass and
a seven minute
hourglass.
You do have a stove however
with water in a pot already boiling.
Somebody asks you for a nine minute egg, and you
know this person is a
perfectionist and will be able to tell if you
undercook or overcook the
eggs by even a few seconds. What is the least amount
of time it will
take to prepare the egg?
***************************
***************************
Place 5 queens on the chess board, such that all the
squares on the board get queen support
***************************
***************************
Place 8 queens on the chess board, such that none
gets in the way of any other (none can kill other)
***************************
***************************
A pick-up truck is in the desert beside N 50-gallon
gas drums, all full.
The truck's gas tank holds 10 gallons and is
empty. The truck can carry
one drum, whether full or empty, in its bed.
It gets 10 miles to the
gallon. How far away from the starting point can you
drive the truck?
***************************
***************************
As you leave your house in the morning, you can feel
the portent of
snow in the air. The weather report on the radio
confirms your
suspicions.
Sure enough, the snow begins to fall before
noon-time, and falls at a
constant rate. The city sends out its first snow
plow at
begins removing snow at a constant rate (in cubic
feet per minute.)
At
still not retracing its path.
At what time did it start to snow?
***************************
***************************
Is a round-trip (anywhere) by airplane longer or
shorter if there is wind blowing?
***************************
***************************
Two spheres are the same size and weight, but one is
hollow. They are
each made of uniform material, though of course not
the same material.
With a minimum of apparatus, how can I tell which is
hollow?
***************************
***************************
Which Box Contains the Gold? Two boxes are labeled
"A" and "B". A sign on
box A says "The sign on box B is true and the
gold is
in box A". A sign on box B says "The sign
on box A is false and the gold
is in box A". Assuming there is gold in one of
the boxes,
which box contains the gold?
***************************
***************************
Somewhere on the high sees smuggler S is attempting,
without much luck, to
outspeed coast guard G, whose boat can go faster than S's. G is
one mile east of S when a heavy fog descends. It's
so heavy that nobody
can see or hear anything further than a few feet.
Immediately after the
fog descends, S changes course and attempts to
escape at constant speed
under a new, fixed course. Meanwhile, G has lost
track of S. But G
happens to know S's speed, that it
is constant, and that S is sticking to
some fixed heading, unknown to G. How does G catch S? G may
change
course and speed at will. He knows his own speed and
course at all times.
There is no wind, G does not have radio or radar,
there is enough
space for maneuvering, etc.
***************************
***************************
Arrange 10 points so that they form 5 rows of 4
each.
***************************
***************************
A body of soldiers form a 50m-by-50m square ABCD on the parade ground. In
a unit of time, they march forward 50m in formation
to take up the
position DCEF.
The army's mascot, a small dog, is standing next to
its handler at
location A. When the soldiers start marching, the
dog begins to run around
the moving body in a
clockwise direction, keeping as close to it as
possible. When one unit of
time has elapsed, the dog has made one complete
circuit and has got back
to its handler, who
is now at location D. (We can assume the dog runs at
a constant speed and
does not delay when turning the corners.)
B----C----E
| |
| forward-->
A----D----F
How far does the dog travel?
***************************
***************************
/* for "C" programmers :
If the output of the following program is
"Z Y X W V U T S R Q P O N M L K J I H G F E D
C B A " (no quotes)
what would "myheader.h"
contain ?
Here is the Program : */
#include <stdio.h>
#include "myheader.h"
void main(void)
{
int i;
for(i = 'A'; i <= 'Z'; i++)
printf("%c
", i);
}
***************************
***************************
Real gummy bears have a mass of 10 grams,
while imitation gummy
bears have a mass of 9 grams. Spike has
10 cartons, each containing
100 gummy bears, some of which contain real gummy
bears, the others imitation.
Using a scale (spring balance) only once
and the minimum number of gummy bears, how
can Spike determine which cartons contain real
gummy bears?
***************************
***************************
***************************
***************************
It's based on High
school geometry :
You are
given a sheet of paper which contains
three
parallel lines drawn on it. Distances between
the lines
need not be the same.
Using
standard allowable construction apparatus
(scale
and a compass and a pencil) construct an
equilateral triangle, such that each of its vertices
lies on
the three different parallel lines.
Note : the lines are theoretically infinite lines,
so you
are allowed to extend those in either directions
if
required
Extension :
Fit an
equilateral triangle on 3 concentric circles (each vertex on different circles)
***************************
***************************
A farmer owns a rectangular farm (a X b units) . Somewhere inside the farm, a
significantly large rectangular portion
(c X d units) is completely useless. Farmer wants to
divide the useful area of
the farm equally between
his two sons.
The fence has to be along a straight line.
Suggest the easiest solution.
***************************
***************************
Take 5
coins, 3 of same devaluation & 2 of other.
Say 3 two rupee coins & 2 one rupee coins.
They are
arranged as follows
2 1 2 1 2
1. There is no gap between adjacent coins (adjacent coins touching).
2. You
can move a pair (compulsory mixed) of adjacent coins with
your
fingers.
i.e. you can't move a pair 2 2 or
1 1, also you can't move a pair
if the
coins are not touching.
3. While moving, you cant's rotate,
i.e. 2 1
can not be made 1 2 by jugglery of fingers. (neither can be made 2 over 1)
And
Final
position to be achieved is
1 1 2 2 2
(again
adjacent coins touching).
***************************
***************************
There's a prison with 100 cells(all have doors/gates).
Initially all the gates are closed. A cop comes in
and opens all the 100
gates. II one comes in and closes every alternate
gate starting from the II
one. III cop checks in and starting from the third
cell every third cell
thereafter he reverses the operation(close
the gate if open and vice-versa)
. IV cop checks in and does a similar operation as
the III cop but he starts
from the IV cell and every IV cell
thereafter.....this goes on till 100 cops
have done with their job of opening/closing of the
gates.
The question is:
What are cells that are
open and those which are closed
finally ??
***************************
***************************
Do the 3 hands on a clock ever divide the face of
the clock into 3
equal segments, i.e. 120 degrees between each hand?
***************************
***************************
whats the thing that differentiates these two groups
AEFHIKLMNTVWXYZ
BCDGJOPQRSU
***************************
***************************
sent by Ajay Patil :
A, B, C and D are very good friends, so good that
whenever one gets some money, he keeps one forth (25%) of the money to himself and
distributes the remaining sum with the other three equally.
So, if A gets 100 rupees,
he'll keep 25 for himself and give 25 each to B, C, D. But they won't take the
whole of 25 rupees for themselves, they will take 25 %
of 25 and distribute the rest amongst others and so on...
Suppose I give Rs. 5000
to A, 10000 to B, 15000 to C and 20000 to D, eventually after all distribution
and transactions are over, how much money each one gets ?
***************************
***************************
Sent by Aniruddha Kelkar :
Given a loop of rope - (which doesn't have start or
end - or, start and end are tied to each other).
and n verticle poles having
infinite hight.
Arrange the loop around those n infinite height
poles, such that
loop can not come out.
On removing ANY
Hint : Try it for 1, 2, 3 first - then generalize
***************************
***************************
Sent by Ajay
Patil :
Q4. Given below is a long hand division sum where
all the
digits except one are replaced by *'s. Usual
conventions are
followed.
* * * 7 *
------------------
* * * ) * * * * * * * *
* * * *
---------
* * * *
* * *
---------
* * *
* * *
-------
* * * *
* * * *
---------
How many solutions are there?
A. No solution
B. 1
C. 2
D. 12
E. 108
***************************
***************************
Sent by Kedar Mhaswade :
Given a pointer to any link in a singly linked list
(Every member has a member *next does not have member *previous) find an
elegant way to determine if the link list loops i.e. next of one of the
elements points to one of the previous elements (is it also called closed link list ?)
***************************
***************************
A pirate ship captures a treasure of 1000 gold
coins. The treasure has to
be split amongst the five pirates
: 1,2,3,4 and 5 in order of rank. The
pirates have the following
important characteristics :
Infinitely clever
Bloodthirsty
Greedy
Starting with pirate 5, they can make a proposal
of how to split the
treasure. This proposal can either be accepted, or
the pirate is thrown
overboard. A proposal is only
accepted if, and only if, the majority of pirates
agree on it.
What proposal should pirate 5 make
?
***************************
***************************
Five people go to a Mesopotamian restaurant. Not
being familiar with such
food, they do not recognise
any of the names for the dishes. Each orders
one dish, not necessarily distinct. The waiter
brings the dishes and
places them in the middle, without saying which is
which. At this point,
they may be able to deduce some.
For example, if two people ordered the same item,
and everyone else
ordered different dishes, then the item of which two
copies arrive must be
the one of which two were ordered.
They return to the restaurant two more times,
following the same drill,
though with different orders. After three meals,
they have eaten all nine
items on the menu, and can tell which is which.
Part A : What pattern of ordering fulfils this?
Part B : Show that the
story couldn't be true if the number of items on
the menu were ten instead of nine.
***************************
***************************
Just move one matchstick to make the following equation
approximately true
***************************
***************************
Courtesy by Syam Sunder :
Find a 10 digit number in which the digit at index i from left is same as the number of times "i" appears in the number.
So if leftmost (at index = 0) digit of the number is 2, the number itself should have 2 zeroes.
To give an example of which is not a valid array
and why is as follows :
3240032115 -
Here digit at 0th place is 3 and 0 does appear 3
times in the number - condition satisfied
At index = 1, number is 2 and 1 does appear 2 times
in the number - condition satisfied
At index = 2, number is 4 but 2 does not appear 4
times in the number * condition not satisfied !
- So it is not a valid number.
For a correct number, the condition should
satisfy at all the 10 decimal places.
***************************
***************************
Courtesy Bhalachandra Kulkarni :
While driving home across a desert
road, the car of a young family breaks down . Their house is ten miles away,
and it is late afternoon. Mum desperately wants all of them to get home before
nightfall. She opens the boot of the car, and takes out the family bicycle.
She figures that her daughter Amy, and her son Ben can walk at 2mph, but can ride the
bicycle at 12mph. She can walk at 4mph and ride the bike at 16mph. The bike
isn't very sturdy and only one of them can ride it at any one time.
Can you figure out the fastest way for the whole family to get home, and how long it takes ?
***************************
***************************
Courtesy Bhalachandra Kulkarni :
Everyday a husband arrives at station where his wife comes there in a car and picks him up at a certain fixed time. One day huband arrives one hour earlier. Instead of waiting there he starts walking towards his house. His wife meets him in between and both reach home 10 minutes earlier than their regular time.
How much time was he walking ?
***************************
***************************
Courtesy Bhalachandra Kulkarni :
A train which runs at speed
40km/hr starts from Pune. At the same time a bird who flies at 80km/hr starts from Mumbai. As soon as he meets
the train he flies back to mumbai and again returns ,again meets the train ,flies back to mumbai and so forth , till train reaches mumbai.The distance between pune mumbai is 160 km.
How much distance does the bird fly ?
***************************
***************************
Courtesy Bhalachandra Kulkarni :
If a man climbs a
hill at 40 km/hr and climbs down at 60 km/hr
What is his average speed ?
***************************
***************************
Courtesy Bhalachandra Kulkarni :
If you have rectangular rod
shaped magnet and an iron piece both identical in shape, size and looks.
How will you identify which one is which without suspending them in air.
***************************
***************************
Courtesy Bhalachandra Kulkarni :
There are four persons A,B,C,D who want to cross a bridge at night and have only one
lamp.
Each of them crosses bridge in 10,5,2,1 minutes
respectively.
At a time ,maximum two
persons can cross the bridge and its impossible to cross the bridge without the
lamp.
So one of the persons who crosses
the bridge must return with the lamp to get others on opposite side.
They have to cross the bridge in 17 minutes.
How should they do that ?
***************************
***************************
Courtesy Amit Jain
On a standard analogue clock
(dial shows 12 hours, no seconds hand), in a 12 hour period (say from
Can you generate a list if the
times when this is possible ?
(Einstein solved the first part in 2 minutes).
***************************
***************************
Find a rectangular solid where
the 12 edges and both diagonals on all 6 faces are integers.
***************************
***************************
The descriptor sequence is a sequence
of numbers in which the digits of each number describe the preceding number.
The first number is 1. This number consists of one 1, so the second number is 11
(that is, one-one). This consists of two 1's, so the third term is 21. This
consists of one 2 and one 1, so the fourth term is 1211. The first six numbers
in the sequence are
1, 11, 21, 1211, 111221, 312211.
Show that no digit greater than 3 ever occurs,
and that the sequence 333 never occurs.
***************************
***************************
You are given 2 long ropes - of
different materials. and match box.and
nothing else.
Both the ropes are composed of
highly heterogenious materials. i.e.
some of the portion is made up of nylon, some cotton, some jute and so on.
But you have been told that if
lit at one end, each rope completely burns upto the
other end in exactly 1 hour. But being composed of different materials, you are
aware that the speed of burning would be highly variable.
Using this apparatus and this info, can you measure time of 45 minutes exactly ?
***************************
PUZZLE 75
***************************
Use digits 1,2,3,4,5,6,7,8,9
– each only once - and create a nine-digit number such that :
1. number formed by
first 2 digits is divisible by 2.
2. number formed by
first 3 digits is divisible by 3.
3. number formed by
first 4 digits is divisible by 4.
....
....
8. number formed by
first 9 digits is divisible by 9.
Find the nine-digit number
***************************
PUZZLE 76
***************************
(BA+BY) * (BA+BY) =
Determine A, B, Y
***************************
PUZZLE 77
***************************
A^B + B^A = 2500
Determine A, B
***************************
PUZZLE 78
***************************
Starting with a deck of 52 cards, 10 cards are
turned upside down and shuffled randomly back into the deck.
Without looking at the cards, create two piles of
cards that have the same number of upside down cards.
***************************
PUZZLE 79
***************************
There are 8 people trying to cross a river. Some of
them have got cannibal instinct.
You are given the following information and asked
to help everybody cross the river safely.
1. Eight people consist of one thief (T), one
policeman (P) and 6 member of a family - husband (H), wife (W), 2 boys (B1,
B2), 2 girls(G1, G2)
2. We have got only one boat.
3. Policeman, husband and wife are the only
people who can pool the boat. At least one of them have
to be in the boat for boat to cross the river
4. Boat can accommodate only 2 people at any
given point of time.
5. Thief can eat anybody in the absence of police
– as soon as he gets an opportunity
6. Husband can eat girls in the absence of wife
– as soon as he gets an opportunity
7. Wife can eat boys in the absence of husband as
soon as she gets an opportunity
8. policeman doesn't
interfere in family matter, means husband/wife can eat girl/boy even if
policeman is there.
9. Person in the boat is not safe if the boat is
at that bank of the river where there's someone who can hurt this person.
10. Person in the boat can hurt person on the
bank if the boat is at that bank of the river where there's someone whom s/he
can hurt.
Please list down the steps
***************************
PUZZLE 80
***************************
Take a 5 litre and 3 litre bucket to the river and get
me 4 litres of water
***************************
PUZZLE 81
***************************
A bank has 3 Fixed Deposit schems
1. Money doubles in 2 years
2. Money triples in 3 years
3. Money quadruples ( 4times
) in 4 years
Which option is best for investment?
Note: Time allowed to solve is 1 min. :)
***************************
PUZZLE 82
***************************
- Suppose that you have a grid with 1cm^2 squares.
Now you have a sheet of paper with a size same as that of the entire grid (say
the grid is 1 m^2). There are one or more drops of ink on this paper, such that
the sum of areas of all of these drops is < 1cm^2.
Can you prove that you can always align/adjust
the grid over this paper such that none of the intersections of the grid will
fall on (any
of) the drops?
***************************
PUZZLE 83
***************************
Suppose that you have a stream of integers
available for reading. There is something interesting about integers found in
the stream:
-- All the integers will repeat once (i.e. they
are in pair) till the EndOfStream is reached, except one
integer.
Now, write a program to find the unpaired
integer, when the EndOfStream is reached.
Note: You have no restrictions on physical
resources.
I think there are 2 solutions, one of them
elegant,
the other one less so.
***************************
PUZZLE 84
***************************
Substitute digits for the letters to make the
following multiplication true.
N
O W
x O
R
--------------
N E
V E R
Note that the leftmost letter can't be zero in
any word. Also, there
must be a one-to-one mapping between digits and letters. e.g. if you
substitute 9 for the letter R, no other letter can be 9 and all
other R in
the puzzle must be 9.
***************************
PUZZLE 85
***************************
Prove that:
LCM(x,y) * GCD(x*y)
= x * y
***************************
PUZZLE 86
***************************
On paper 3 parellel
lines are drawn.
Construct an equilateral triangle such that each
vertex lies on each line
***************************
PUZZLE 87
***************************
On paper 3 concentric circles are drawn.
Construct an equilateral triangle such that each
vertex lies on each line
***************************
PUZZLE 88
***************************
In a closed box there are three different types of alien amoebae
trapped say A, B & C.
It is known that any two types of these amoeba
can merge to give the third type.(i.e. A + B = C, B + C = A & C + A = B).
Initially there were 42 of A, 21 of B & 84 of
C type. After a long time if is found that only one amoeba is left in the box.
What is its type??
***************************
PUZZLE 89
***************************
Thirty coins are arranged in a row facing H, T, H, T. ......H, T. (H
means Head facing up & T for Tail). A move consists of flipping over any 2
adjacent coins.
What is
the minimum number of moves required to get all the coins facing H??
***************************
PUZZLE 90
***************************
The numbers 1, 2, 3, 4, 5, 6...............,90 are written on a horizontal line.
Using either a "+" sign or a
"-" sign between adjacent numbers, the resulting expression when
evaluated, turns out to be 0. Is the preceding statement true??
***************************
PUZZLE 91
***************************
A bag given to you contains apparently similar, 51 type A coins
& 50 type B coins. The only difference between a type A
coin & a type B coin is that their weights differ by 1 gram. You are also
given an digital weighing machine which always
displays the positive difference between the contents of its pans.
Now, if I remove a coin from
that bag and ask you to tell me whether its type A or B using the weighing
machine only once.... can you tell that?
***************************
PUZZLE 92
***************************
5 couples - different number of handshakes - no
handshake with spouse
how many host had ?
***************************
PUZZLE 93
***************************
9 people - different number of handshakes
how many host had ?
***************************
PUZZLE 94
***************************
There is a circle and there are 2 million points
inside the circle
Device a strategy to draw a straight line through
the circle that divides the circle in 2 parts such that 1 million points on one
side and 1 million on other and no point lies on the line.
***************************
PUZZLE 95
***************************
There are 30 horses. You have to decide top
These are the rules :
1.
In one race only 6
can compete
2. No two horses have same speed
3. All horses run at identically same speed in every race
***************************
PUZZLE 96
***************************
There are 9 horses. You have to decide their
order from 1st to 9th according to speed by having
*MINIMUM* number of races between them.
These are the rules :
1.
In one race only 3
can compete
2. No two horses have same speed
All horses run at identically
same speed in every race
***************************
PUZZLE 97
**************************
A squint man has a visual deflection of 30 degrees. This means that
there is a 30 degrees angle between the direction that he sees as straight and
the direction that he walks in. How long is the path of his walk when he can
see that he is walking straight towards a pole that was 100 metres
away from him at the beginning?
Note: It is possible (and the preferred way, actually) to solve this puzzle
without using integral calculus
***************************
PUZZLE 98
**************************
There are 25 hungry and extremely smart lions in
a cage into which a portion of food is thrown. The following rules, known by
the lions as well, apply:
·
One portion of food
can either fully be eaten by a lion or it can remain untouched, but it cannot
be shared between two or more lions.
·
If a lion eats the
food, he gets satisfied and falls asleep.
·
A sleeping lion is
considered as one portion of food, just the same portion of food he has eaten.
Thus, a sleeping lion can be eaten by another lion (in which case that lion
will fall asleep, and so on).
·
The lions are hungry,
but they are fed properly, so they won't die if they don't eat extra food.
·
All the lions like to
eat extra food and they don't care if a fellow dies in the process.
·
They are smart: a
lion will not eat any extra food if it can be known that he would be eaten if
he ate it.
Question is: what happens when the extra food is
thrown in?
***************************
PUZZLE 99
**************************
In a family one of the two children is a boy.
What is the probability that the other child is a girl?
Do you want to share the interesting logical puzzles you know ?