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December 31, 2009

Blindfold game

A blindfolded man is asked to sit in the front of a carrom board.
The holes of the board are shut with lids in random order, i.e. any
number of all the four holes can be shut or open. Now the man is
supposed to touch any two holes at a time and can do the following.
* Open the closed hole.
* Close the open hole.
* Let the hole be as it is.
After he has done it, the carrom board is rotated and again brought
to some position. The man is again not aware of what are the holes
which are open or closed.

How many minimum number of turns does the blindfolded man require
to either open all the holes or close all the holes?
Note that whenever all the holes are either open or close, there
will be an alarm so that the blindfolded man will know that he has won.

Birthday Probability Problem

What are the chances that at least two out of a group of fifty people
share the same birthday?

December 28, 2009

Find the sum of digits ?

Find sum of digits of D.
Let A= 19991999
B = sum of digits of A, C = sum of digits of B, D = sum of digits of C.

December 18, 2009

Cube puzzle

If you take a marker and start from a corner on a cube, what is the
maximum number of edges you can trace across if you never trace
across the same edge twice, never remove the marker from the cube,
and never trace anywhere on the cube, except for the corners & edges?

December 14, 2009

Find the probability

In a hotel, rooms are numbered from 101 to 550. A room is chosen
at random. What is the probability that room number starts with
1, 2 or 3 and ends with 4, 5 or 6?

December 7, 2009

Find the ages of the chidren ?

Many years from now, two classmates met in a street.

The following is part of their discussion.

Student 1: Yes, I'm married and have three wounderful children.
Student 2: That's great! How old are they?
Student 1: Well, the product of their ages is 36.
Student 2: Hmm. That doesn't tell me enough. Give me another clue.
Student 1: OK. the sum of their ages is the number on that building
across the street.
Student 2: (After a few minutes of thinking with the aid of pencil and paper)
Ah ha! I've almost got it but I still need another clue.
Student 1: Very well. The oldest one has red hair.
Student 2: I've got it!

What were the ages of the children of student 1?

December 1, 2009

Last words of the soldier...

A soldier has been captured by the enemy and is sentenced to die.
His captors say: "You may make a statement. If you tell a lie, you will
be shot. If you tell the truth, you will be hanged."
He makes a statement and goes free. What could he have said?

November 26, 2009

November 25, 2009

Eight queens problem

Place 8 queens in 8X8 chessboard such that none of them able to
capture any other by standard moves of queen. That is no 2 queens
would be able to attack each other.
[also try general queens problem of placing n queens in nxn chessboard]

November 10, 2009

Find the length of the bridge ?

There is a river which is 4100 inches wide, and the bridge across the
river is in such a way that one seventh of the overall length of the
bridge was on one side of the river and one eighth of the bridge was
on the other side of the river.
Find the total length of the bridge?

[Note: The bridge perfectly straight]

November 2, 2009

Chess board problem

what is maximum no. of kings which can be placed on a chessboard so
that no 2 of them put each other in check?
[provided all kings are of one color and check rule is applicable to
same color kings]

October 22, 2009

dumb & deaf

How can a deaf man without the help of anyone confirm that
he is not dumb?

October 12, 2009

15, 161, 1771, 19481, 214291,______?

Next number in the sequence
15, 161, 1771, 19481, 214291 is


1) 1942651
2) 135611101
3) 2424561
4) 1357101
5) 345372101
6) 1357201
7) 23651121
8) 1764924
9) 125461
10) 234255

September 24, 2009

A man wanted to get into his work building....

A man wanted to get into his work building, but he had forgotten
his code. However, he did remember five clues.
These are what those clues were:

# The fifth number plus the third number equals fourteen.
# The fourth number is one more than the second number.
# The first number is one less than twice the second number.
# The second number plus the third number equals ten.
# The sum of all five numbers is 30.

What were the five numbers and in what order?

September 22, 2009

Hourglass puzzles

You have two sand hourglasses, one that measures exactly 4 minutes
and one that measures exactly 7 minutes. You need to measure out
exactly 2 minutes to boil an egg. Using only these two hourglasses,
how can you measure out exactly 2 minutes to boil your egg?

September 9, 2009

Amazing Sentences

Write a meaningful sentence of 15 words in such a way that the first
word is of one letter long, second word of two letters, third word
is three letters long ............ 8th word is 8 letters long
and so on ... until the 15th word is 15 letters long !!!

(If you are successful with 15 words then try using 20 words)

Prisoners and hats puzzles

4 prisoners are caught and are to be punished. The Judge allows them
to be freed if they can solve a puzzle.
If they do not, they will be hung. They agreed.

The 4 prisoners are lined up on some steps (shown above). They are
all facing in the same direction. A wall separates the fourth man
from the other three.

So to summarize:-
Man 1 can see men 2 and 3.
Man 2 can see man 3.
Man 3 can see none of the others.
Man 4 can see none of the others.

The prisoners are wearing hats. They are told that there are two white
hats and two black hats. The men initially don't know what colour
hat they are wearing. They are told to shout out the color of the hat
that they are wearing as soon as they know for certain what colour
it is.

They are not allowed to turn round or move.
They are not allowed to talk to each other.
They are not allowed to take their hats off. Who is the first person
to shout out and why?

August 26, 2009

100 doors in a row problem

There are 100 doors in a row numbered from 1 to 100. Initially all
are closed. Then you make 100 passes by the 100 doors. In pass 1 you
toggle the all the doors (1,2,3,4....)starting from the first door.
In the second pass you toggle every second door(2,4,6,8,...). In the
third pass you toggle all third doors (3,6,9...). Similarly you make
100 passes.

what state are the doors in after the last pass?

which are open which are closed??

August 24, 2009

Unusual paragraph

What is unusual about this paragraph? You will find that this is not
just an ordinary paragraph if you look at its words. An odd group of
words this is! Can you find what it is?

August 11, 2009

Golo is locked in a cave !!!

Golo is locked in a cave. He is having 2 vessels with him (5ltr & 7ltr).
The gate of the cave will open only when there are exactly 6 litres on
the handle. He can take as much water as he want from the nearby
water well. How he can make combinations such that the 7 ltr vessel
will have exactly 6 liters of water?

August 5, 2009

64 = 65 Geometry Paradox

Comparison of the areas of the 2 shapes creates a paradox: 64 = 65

How is this possible?

July 28, 2009


Each of the letters in the equation below represents one of the
digits from 0 to 9. Determine which digit corresponds to each letter.


July 22, 2009

Race track problem

A Race track is one mile long, if a driver goes around once at
30 miles per hour, how fast must he drive in the second lap to
average sixty miles per hour over both laps?

July 15, 2009

Logic riddles

A horse have to transfer bananas from one point to the other point
(points are 1000km apart). He can take atmost 1000 bananas at a time
and he eats 1 banana after every km he travels. Tell me the
maximum no. of bananas he can take to the final point if the total
no. of bananas are 3000 ?

July 9, 2009

The ultimate age problem

Varun is 33 years old. This is three times as old as Tharun was when
Varun was as old as Tharun is now...

How old is Tharun now ?

July 7, 2009

Clock time puzzles

If it were two hours later, it would be half as long until midnight
as it would be if it were an hour later.

What time is it now?

June 22, 2009

Tricky puzzles

A bottle of soda costs $3. The soda is worth $2 more than the bottle.
How much is the bottle worth?

June 12, 2009

The Monty Hall Trap

“Suppose you are on a game show, and you are given the choice
of three doors: Behind one door is a Rolls Royce car and behind
the others, goats. Let's assume that you would prefer a Rolls Royce
to a goat. You pick a door, say No.1, and the host, who knows
what's behind the doors, opens another door, say No.3, which has
a goat. He then says to you, "Do you want to pick door No. 2?

Is it to your advantage to switch your choice?”

June 9, 2009

The toy vendor puzzle

A toy vendor is selling toys from door to door.He visits a house
& asks the owner lady to buy toys for her kids. Lady, being a
smart customer, says to Toy Vendor “If you can tell me the ages
of my 3 Kids correctly then only I will buy Toys from you.”
Toy Vendor says “OK M’am , Please give me some clue”

“If you multiply ages of my 3 kids you get figure 36.And if you add
ages of my 3 kids you get House Number of my neighbour” replies Lady.

Toy Vendor thinks for a while , goes & notes Number of Neighbour’s
house & returns saying “M’am , some more information is required”

“OK, my eldest daughter plays Harmonium very nicely” replies Lady.
“Oh, in that case I have got answer to your question”
replies Toy Vendor & tells the Lady the correct ages of her Kids.

Can you tell ages of Lady’s Kids ?
What is House Number of Lady’s Neighbour ??

June 5, 2009

Famous Logic Puzzles

A king wants an advisor and comes to ask the 3 wisest sages.
He blindfolds them and put the hats on their head. Afterwards,
the king takes off their blindfolds. He tells them that
their hat is either blue or white. He tells them that whoever
can deduce the color of their hat will be his next advisor.
Also he tells them that at least one of the sages will be
wearing a blue hat. The sages can all see each other's hats
except of course, their own. Sage A sees that the other 2 are
wearing blue hats.
For hours no one spoke, then Sage A stands up and tells the
king the colour of his hat. What color is it and how does he know?

May 29, 2009

Number Lock Problems

There is a safe with a 5 digit Number lock. The 4th digit is 4
greater than second digit, while 3rd digit is 3 less than 2nd digit.
The 1st digit is thrice the last digit. There are 3 pairs whose
sum is 11. Find the number ?

May 21, 2009

Lateral Thinking Problems

1)How could a baby fall out of a twenty-story building onto
the ground and live?

2)There are six eggs in the basket. Six people each take
one of the eggs. How can it be that one egg is left in the basket?

May 15, 2009

Flight path puzzle

There are 9 cities numbered 1 to 9. From how many cities a flight
can start so as to reach the city 8 either directly or indirectly
such the path formed is divisible by 3

eg. 1368-Flights goes from 1 through 1-3-6-8 to 8.

May 5, 2009

Profit & Loss questions

A man decides to buy a nice horse. He pays $60 for it, and he is
very content with the strong animal. After a year, the value of
the horse has increased to $70 and he decides to sell the horse.
But already a few days later he regrets his decision to sell the
beautiful horse, and he buys it again. Unfortunately he has to pay
$80 to get it back, so he loses $10. After another year of owning
the horse, he finally decides to sell the horse for $90.

What is the overall profit/loss the man makes?

April 27, 2009

Mary's Car

The Old car of Mary requires tyres to be changed after each 24000 km.
If she wants to go for 42000 km journey then how many minimum
number of tyres she will need ?

April 22, 2009

There is a bus with 7 girls........

There is a bus with 7 girls.

Each girl has 7 bags.

In each bag, there are 7 big cats.

Each big cat has 7 little cats.

Each cat has 4 legs.

How many legs are present in the bus?

April 17, 2009

Cake cutting puzzle

What is the maximum number of slices can you obtain by cutting
a cake with only 4 cuts?

April 9, 2009

Clock Puzzles

If a clock takes 7seconds to strike 7, how long will the same
clock take to strike 10?

April 6, 2009

Pond with Lillies

There is one lily in the pond on 1st june. There are two in
the pond on 2nd june . There are four on 3rd june and so on.
The pond is full with lilies by the end of the June.

(i) On which date the pond is half full?

(ii) If we start with 2 lilies on 1st June when will be the pond
be full with lilies.


There are 19 red balls and one black ball. Ten balls are put
in one jar and the remaining 10 are put in another jar.
What is the possibility that the black is in the right jar.

April 2, 2009

Probability Riddles

Two Persons A and B. Person A picks a random number from 1 to 1000.
Then person B picks a random number from 1 to 1000. What is the
probability of B getting number greater then what A has picked?

Escalator Puzzles

There is an Escalator and 2 persons move down it.A takes 50 steps
and B takes 75 steps while the escalator is moving down.
Given that the time taken by A to take 1 step is equal to time taken
by B to take 3 steps. Find the no. of steps in the escalator
while it is stationary ?

March 30, 2009

The Ultimate Puzzle

This is a story of four boys - Chinku, Dinku, Pinku and Tinku.

One day all of them decide to save their money in a bank(Joint Account).
They select a bank called “Lena Bank”

The bank's specialty is: In every month the money gets doubled.

In 2nd month, Chinku withdraws 100-Rs from bank.

In 3rd month, Dinku withdraws 100-Rs from bank.

In 4th month, Pinku withdraws 100-Rs from bank.

In 5th month, Tinku withdraws 100-Rs from bank.
Then their balance in the bank becomes zero.

How much amount had the boys put in the bank?

March 24, 2009

2 Batsman are on 94 problem ?

2 batsman r on 94. 2 balls remaining & 7 runs to win.
and both the batsman make their century & win match How?

March 20, 2009

Challenging Problem

Just spell the numbers as one, two, three, .........
Now tell me which will be the shortest number
containing "Least number of "a" irrespective of the place"

March 17, 2009

Be puzzled

A hotel has 10 floors.
Which floor is above the floor below the floor,
below the floor above above the floor,
below the floor above the fifth ?

March 10, 2009

Date of birth puzzle

Ninu was born on 3rd march 1980. Mini was born 4 days before nenu.
The Republic Day of that year fell on a saturday.
Then Mini's birthday was on

(a) Sunday

Logic brain teaser

There are 1000 soliders with a no. on their T Shirts
(1,2,3.....999,1000) standing on a circular track.
Man with no.1 is carrying a sword in his hand.
He kills man at no. 2 and pass on sword to no. 3.
This goes on until we have only one solider on the track.
What will be the no. on his T-Shirt?

February 25, 2009

Train Puzzle

Two stations connected by railroad. Trains start every hour
from each station to the other , at the same time.
A Train takes 5 hours to reach the other station.
How many trains will a train meet during its journey?

February 18, 2009

Dice problem

Two people are playing with a pair of dies. Instead of numbers,
the dies have different colors on their sides. The first person wins
if the same color appears on both the dies and the second person
wins if the colors are different. The odds (chance)of their winning
are equal. If the first dice has 5 red sides and 1 blue side,
find the color(s) on the second one.

[really tough one]

February 16, 2009

Hilarious Puzzles

You are stuck in a room with no windows, and no doors.
The only thing in the room is a table and a mirror.
How do you get out?

February 9, 2009

Probability Problem

There are 3 bags. One contains 2 gold coins, another has
2 silver coins and the 3rd has one of each. You pick a bag
at random, and without looking inside take out one coin.
It's gold. What is the probability that the other coin
in that bag is also gold?

Bridge crossing problem

A group of four people has to cross a bridge. It is dark,
and they have to light the path with a flashlight.
No more than two people can cross the bridge simultaneously,
and the group has only one flashlight. It takes different
time for the people in the group to cross the bridge.
When two people together goes through the bridge,
the time taken by them to cross the bridge is the time taken
by the person with highest crossing time:

A crosses the bridge in 1 minute,
B crosses the bridge in 2 minutes,
C the bridge in 5 minutes,
D crosses the bridge in 10 minutes.

What is the minimum time in which they can cross the bridge.........???

Give with explanation.......!!!!!!!!

February 5, 2009

Tricky question

Mary's father has five daughters:

1. Nana
2. Nene
3. Nini
4. Nono

What is the name of the fifth daughter?

January 30, 2009

Clock time problem

A girl buys a clock 2 weeks back. This clock loses 24 mins
in every one hour time. You set the time at 12 midnight
and the clock now displays 3.00 am and it was stopped one
hour back from now. So,what is the actual time now?

January 29, 2009

Train & tickets

Every station in a rail road issue every other station's ticket.
Some stations are added. Now they have to issue 46 more tickets.
The number of stations before and after addition is ?

Man and dog problem

A man is taking his dog for a walk. They set off together for a
waterfall 10 miles away. They set off exactly together and the
man walks at a steady 4 miles an hour. The dog runs off at 8 miles
an hour and when it reaches the waterfall it turns round and
runs back to the man. When it reaches the man it turns round and
runs back to the waterfall and so on until the man and dog arrive
at the waterfall. when they both arrive at waterfall ?

January 27, 2009

Critical Thinking Puzzles

Figure out how many gold medals Canada, Austria, Norway,
the Netherlands, Japan, Italy, Russia, and the United
States received.

1. Norway won five times as many gold medals as Russia.

2. The eight countries won a total of fifty-nine gold medals.

3. Russia has one more gold medal than Italy.

4. If Japan won four more gold medals, they would have won the
same number of gold medals as Canada.

5. The Netherlands won eight more gold medals than one-third
the number of gold medals won by Austria.

6. If Canada had won one more than three times the number
of gold medals, they would have won thirteen more gold
medals than the United States.

January 20, 2009

Funny riddle

If the puzzle you solved before you solved the puzzle you solved
after you solved the puzzle you solved before you solved this one,
was harder than the puzzle you solved after you solved the puzzle
you solved before you solved this one, was the puzzle you solved
before you solved this one harder than this one ?
Explain your reasoning.

Shadow length

A pillar 6 feet tall casts a shadow 3 feet long on the ground.
If the pillar was 12 feet tall, how many feet in length
would the shadow be ?

January 16, 2009

Faulty coin problem

You are given twelve coins, of which eleven are genuine
and one is fake. All eleven genuine coins have the same weight
and the fake coin has a different weight. Find the fake in
three weighings.

Probability Puzzle

If a test to detect a disease whose prevalence is one in a
thousand has a false positive rate of 5%, what is the chance
that a person found to have a positive result actually has
the disease, assuming you know nothing about the person’s
symptoms or signs?

January 9, 2009

The six dice problem

There are six unloaded die.
Each has been rolled out of your sight and hidden behind a cup.
You are informed that no more than one of them landed a 6 - but
it may be that none of them did.

You are going to remove the cups one at a time.

Before you do, you label each cup with letters A to F.
This designates the order in which you will remove them.
You have complete discretion which cup is assigned each letter,
but once labeled they must be removed in alphabetical sequence.

Having labelled them, it is time to remove the cups accordingly from A to F.

If one of the dice landed as 6, under which cup is it most likely to be found?

Handshake Problem

Jack and his wife went to a party where four other married
couples were present. Every person shook hands with everyone
he or she was not acquainted with. When the handshaking was
over, Jack asked everyone, including his own wife, how many
hands they shook. To his surprise, Jack got nine different
answers. How many hands did Jack's wife shake ?

January 5, 2009

Lawn Puzzle

Grass in lawn grows equally thick and in a uniform rate.
It takes 24 days for 70 cows and 60 days for 30 cows to eat
the whole of the grass. How many cows are needed to eat
the grass in 96 days?

Substitute digits for the letters

Substitute digits for the letters to make the following relation true.
+ T R A D E

[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 3 for the letter W, no other letter can be 3
and all other W in the puzzle must be 3. ]

Critical Reasoning Puzzle

A blindfolded man is asked to sit in the front of a carrom board.
The holes of the board are shut with lids in random order,
i.e. any number of all the four holes can be shut or open.
Now the man is supposed to touch any two holes at a time and
can do the following.

* Open the closed hole.

* Close the open hole.

* Let the hole be as it is.

After he has done it, the carrom board is rotated and again brought
to some position. The man is again not aware of what are the holes
which are open or closed. How many minimum number of turns does
the blindfolded man require to either open all the holes or close
all the holes? Note that whenever all the holes are either open or
close, there will be an alarm so that the blindfolded man will know
that he has won!!!!!

Find the next in the series


January 2, 2009

8 Ball Problem

You have eight almost identical balls, but one of them is
a little bit lighter than the others. It is not that lighter,
though, that you can tell the difference by hand, but you
have a two-armed balance. How can you find the light
ball with only two measures?

Fun Logic Puzzles

Syam was looking at a photo. Someone asked him, "Whose picture
are you looking at?" He replied: "I don't have any brother or
sister, but this man's father is my father's son."
So, whose picture was Syam looking at?