Friday, May 25, 2018

Strange Creatures on Island

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.

Who are the following two guys?


A: B is a lying monkey. I am human.


B: A is telling the truth.


Identify the creature!

Know who are they! 

 

Identifying the Strange Creature


What was the situation?

 Let's first have statements by 2 creatures

A: B is a lying monkey. I am human.

B: A is telling the truth.


If we assume B is telling the truth then A is also telling the truth. But A in statement says B is lying which contradicts our assumption. 

Hence, B must be lying. If B is lying then statement of B suggest that A is also must be lying. That mean 'B is lying monkey' part of statement made by A is too lie. Since we have deduced already B is lying, the lying statement of A suggests that B is not monkey. Hence B is the lying man!

Other lie spoken by A is that it is human. Hence A must be a lying monkey! 

Lying monkey
 

Forgotten Bank Account Number

Today, John has to transfer 50 euro to the bank account of a Dutch friend. He has written down the account number on a piece paper. But since he had forgotten to take out the paper from his trousers when he put them in the washing machine, one digit of the bank account number became unreadable. The note says: 3170?4847. 

The friend of John is climbing the Mount Everest at the moment, so it is impossible for John to call his friend. Suddenly he remembers that a for a valid Dutch bank account number it holds that the first digit times 9 + the second digit times 8 + the third digit times 7 + ...... + the ninth digit times 1 should be divisible by 11. John thinks for a moment and finds the correct number. 

What is it? 

What is Forgotten Bank Account Number - Maths Puzzle


That it is !
 

Recalling Forgotten Bank Account Number


What were the clues? 

Let x be that missing digit. Then the bank account number looks like, 3170x4847.

Now 9 x First Digit + 8 x Second Digit + 7 x Third Digit.......must be divisible by 11.

That is 27 + 8 + 49 + 0 + 5x + 16 + 24 + 8 + 7 = 139 + 5x must be divisible by 11. 

The only value of x as a digit the satisfies above is 3. With that, total sum 154 is divisible by 11.

Hence, the account number must be, 317034847. 

That's The Forgotten Bank Account Number - Maths Puzzle
 

Breaking The Safe in 5 Minutes?

Charlie Croker and his team need to break the safe to finish a secret job named "Italian Job" in exactly a five minutes.

They got just one chance and five minutes to finish the job else the local police will be informed.

He got following clues

1st Clue: Exactly one number is perfectly placed.
9 2 5

2nd clue: Everything is incorrect.
9 3 8

3rd clue: Two numbers are part of the code of the safe, but are wrongly placed.
4 9 6

4th clue: One number is part of the code of the safe, but is wrongly placed.
5 8 1

5th clue: One number is part of the code of the safe, but is wrongly placed.
1 2 6 


How To Break The Safe in 5 Minutes? - Logical Puzzles


This should be the process!

To Break The Safe in 5 Minutes...


What was the challenge? 

Re listing all the clues...

1st Clue: Exactly one number is perfectly placed.
9 2 5

2nd clue: Everything is incorrect.
9 3 8

3rd clue: Two numbers are part of the code of the safe, but are wrongly placed.
4 9 6

4th clue: One number is part of the code of the safe, but is wrongly placed.
5 8 1

5th clue: One number is part of the code of the safe, but is wrongly placed.
1 2 6 


------------------------------------------------------------------------------------------------

From 2nd clue, it's clear that 9,3,8 are not part of the code.

Hence correct number suggested by 1st clue must be 2 or 5

Since 9 is not part of the code, the other 2 correct numbers that 3rd clue pointing must be 4 and 6.

If 6 is the part of code, then 1 & 2 are not as 5th clue is suggesting.

And since 2 isn't part of the code then 1st clue must be pointing 5 is correct digit placed in right position.

The 4th clue is also suggesting that 5 is the part of the code but not 1 or 8.

If 5 is correct at it's position as per first clue then 4 and 6 must be occupying other 2 places.

As per 3rd clue position of 4 is wrong, it must be at second place and hence 6 at first place.

Hence the code is 645!


Process To Break The Safe in 5 Minutes...Logical Puzzles

A Railway And Cyclist Crossing

A road runs parallel to a railway until it bends to cross it, as shown. A man normally cycles to work along the road at a constant speed of 12 mph, and when he reaches the crossing he’s normally overtaken by a train traveling in the same direction. One day he was 25 minutes late for work and found that the train passed him 6 miles before the crossing. 

What was the speed of the train?

Time At Which A Railway And Cyclist Crossing - Maths Puzzles


Skip To Know The Speed Of The Train! 

To Cross The Cyclist...


What was the scenario?

 Let's suppose he reaches the crossing at 9:00 AM. Usually at 8:30 AM he is at point A, 6 miles before the usual crossing point B (speed of 12 mph, means 6 mile per half hour).

On the day on which he was late by 25 minutes, he must be again at point A (i.e. 6 miles ahead of usual crossing point B) at 8:55 AM. So at this point, both train and man were at the same point A. And the train as everyday, reaches point B at 9:00 AM. That means, it travels 6 miles in 5 minutes. Hence, train must be traveling at 72 mph.  



When Cyclist Crossing Everyday -  Maths Puzzles

When Cyclist Crossing Late day -  Maths Puzzles

Who Was The Thief?

There was a burglary in the Silver City jewelry store last Sunday.

Three suspects: Robert, Scott, and Tommy were caught and questioned.


Each person said, “One of the other two stole it. I did not do it.”

Later on the police found out that Tommy was lying and there was only one thief.

Can you guess who was the thief?


Can You Guess Who Was The Thief? - Logical Puzzles

He must be the thief!

He Must Be The Thief!


Who were suspects?

If the statements made by Tommy are false then it suggests that none of other stole it. That means Tommy himself stole it. Also his other statement where is claiming that he didn't do that is also a lie.

In short, Tommy must be the thief.


Tommy Must Be The Thief! - Logical Puzzles


 

Monday, May 7, 2018

Truth or Lie Puzzle

Out of three people (Lavesh, Mayank and Manoj), one of them is a king, one a bureaucrat, and one a thief.
The king always tells the truth, the bureaucrat always lies, and the thief can either lie or tell the truth.

Lavesh says: 'Manoj is a bureaucrat.'

 
Mayank says: 'Lavesh is a king.'

 
Manoj says: 'I am the thief.'

Who is the king, who the bureaucrat, and who the thief? 


Who is the king, who the bureaucrat, and who the thief?

Find the TRUTH here! 
 

King, Bureaucrat and Theif


What was the story? 

Let's take a look at the statements made by 3.

Lavesh says: 'Manoj is a bureaucrat.'
Mayank says: 'Lavesh is a king.'
Manoj says: 'I am the thief.'


Now let's test truth in each statement.

If we assume Mayank is king and telling the truth than according to him Lavesh is also king. But that's not the possible case.

Now if we assume Manoj is king then his statement must be true where he is saying that he is thief. So how he can be a king & thief at the same time.

Hence, the Lavesh must be a king. Mayank is here telling the truth and hence must not be bureaucrat and hence he is thief. So Manoj is bureaucrat lying in his statement.
 

Identifying King, Bureaucrat and Theif
 

Count Number of F's

Out of how many F's does the following sentence consist?
FINISHED FILES ARE THE RESULTS OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE
EXPERIENCE OF YEARS.


How many F's in given sentence?

Your Count May Be WRONG!

In Between Wrong Count Of F's


Take a look at sentence once again!

Did you count only 3? Really? Here is that sentence written once again.

FINISHED FILES ARE THE RESULTS OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE
EXPERIENCE OF YEARS.


So didn't you count F of word 'OF'? Now how many F's you are finding? 

And that's right! There are 6 F's in the sentence. 


Could Be Wrong Count Of F's
 

Another Game Of Death

Jigsaw forced Mahrez and Vardy to play the game of death.

Jigsaw placed 11 marbles at the table and asked Mahrez and Vardy to pick marble(s) one by one with the following rules:


1. You need to pick at least one marble.
2. You can't pick more than five marbles.

The one that picks the last marble will die.

Mahrez to start the game.

How many marbles must Mahrez pick in order to make sure that he came out from the game alive?


Surviving in Another Game Of Death - Logical Puzzles

This should be Mahrez's Master Plan! 

Surviving In Another Game Of Death


What was the game?

Mahrez should start with the picking 4 marbles.

Now if Varde picks one Mahrez can pick 5 leaving 1 behind for Varde who in turn has to pick it in the end.

Similarly, if Varde picks 2, Mahrez need to pick 4, again leaving 1 behind.

For Varde's pick of 3,4,5; Mahrez should pick 3,2,1 respectively which will always leave behind 1 marble.

This way, Mahrez can easily survive!



Plan for Surviving In Another Game Of Death - Logical Puzzles

Who Stole The Money?

A man placed a $100 dollar bill on his desk and left for work. When he returned back the money was gone. He has three suspects: the cook, the maid and the electrician.

The cook said he put the bill under a book on his desk to keep it safe. The man checked and it is no longer there.

The maid said she moved the bill to the inside of the book between page 1 and 2 while she was cleaning. Again, the man checked the book and there was nothing between page 1 and 2.

The electrician said he saw the bill sticking out of the book and he moved it between page 2 and 3 to keep it safe.

Who stole the money?



Who Has Stolen The Money? - Logical Puzzles
Know who is the thief? 

The Electrician Stole The Money


Who were other suspects?

The electrician must be lying. Since the man checked between page 1 and 2 the next pair of page must be 3 and 4 not 2 and 3. The page numbers 2 and 3 must be the part of single page. 

So how can electrician move it between page 2 and 3? 


Lying Electrician Stole The Money - Logical Puzzles


The Dog Of The Commander

A long and straight row of soldiers is marching with constant speed. The dog of the commander runs along the row from the end till the beginning, from the beginning till the end, from the end till the beginning etc. This takes always 2 minutes, 1 minute, 2 minutes, etc. 

At some point the soldiers have to pass a very small bridge. However, the commander does not trust the strength bridge completely. He wonders how much time it will take them to pass the bridge when they stay marching with the same speed. 


How much time is that?  

Journey of The Dog Of The Commander - Logical Puzzle

You can skip to the answer! 

Passing A Very Small Bridge


What is the question?

For march of soldiers to pass any point, there must be first man crossing that point first and then later the last man should cross the same point. 

Now the dog runs from the first to last man in 1 minute, then runs back to first man in 2 minutes and again back to last man in 1 minutes. That means the dog must be at the same point where he started journey from first man. In other words, the dog has run for 2 minutes in both the directions. Hence, he must be at the same point after 4 minutes.

Soldiers' March Passing A Very Small Bridge - Logical Puzzle
Interestingly, the dog was at first man when started & after 4 minutes ended at the last man of the march. Since dog is at the same point after 4 minutes, the entire march of soldiers is crossed that point in 4 minutes as first and last man have crossed that point.

The same when applied to a very small bridge which can be assumed as a point, we can say that it requires 4 minutes for soldiers to cross it.
 

Who Did It?

Three of these statements are false, so who did it?

    Mr Red: “Mr Blue did it.”


    Mr Blue: “Mr Red did it.”


    Mr Green: “Mr Blue’s telling the truth.”


    Mr Yellow: “Mr Green’s not lying.”


Deduce Who Did it - Logical Puzzles

Find who did it!

Mr. Blue Did it!


What were the statements by suspects?

If Mr. Yellow is telling the truth then Mr. Green and hence Mr. Blue all are telling the truth. This is against the given data.

This hold true if we assume that Mr. Green is telling the truth or Mr. Blue telling the truth. In all cases, 3 statements would be true.

Hence, only statement of Mr.Red is true and that's why Mr. Blue did it!


Mr. Blue has done it - Logical Puzzles
 

The Mongolian Postal Service

The Mongolian Postal Service has a strict rule stating that items sent through the post must not be more than 1 meter long. Longer items must be sent by private carriers, and they are notorious for their expense, inefficiency, and high rate of loss of goods.

Boris was desperate to send his valuable and ancient flute safely through the post. Unfortunately, it was 1.4 meters long and could not be disassembled as it was one long hollow piece of ebony. Eventually he hit on a way to send it through the Mongolian Postal Service. 


What did Boris do?

Dealing With The Mongolian Postal Service - Logical Puzzles

That's what needed for safe delivery! 

Deliverying The Valuable Safely!


What was the problem in delivery?

Boris keeps the flute diagonally in a square shaped suitcase whose side measuring 1m.

Since side is 1 m the diagonal of such suitcase must be square root of 2 i.e. 1.414 m. So the 1 m long flute can easily fit diagonally in such suitcase.


For Deliverying The Valuable Safely! - Maths Puzzles
 

Earnings Of People

Twenty men, women and children earn twenty coins between them. Each man earns 3 coins, each woman 1.5 coins and each child 0.5 coin.

How many men, women and children are there?

How Many Earnings Of People - Maths Puzzle

Find number of each of them here!

Number Of Earning People


What was the question? 

Let's suppose there are m men, w women and c children.

As per given data,

m + w + c = 20   ......(1)

3m + 1.5w + 0.5c = 20   .....(2)

Multiply equation (1) by 3 and then subtracting from (2), we get,

5m + 2w = 20.

For m and w to be whole numbers, m must be 2 and w must be 5 satisfying above equation.

Hence, from (1),

c = 20 - 2 - 5 = 13.


Finding Number Of Earning People - Maths Puzzles
 
To conclude, there are 2 men, 5 women and 13 children.

Draining Reservoir

A large fresh water reservoir has two types of drainage system: small pipes and large pipes.

6 large pipes, on their own, can drain the reservoir in 12 hours.

3 large pipes and 9 small pipes, at the same time, can drain the reservoir in 8 hours.

How long will 5 small pipes, on their own, take to drain the reservoir?


Time For Draining Reservoir

Find here the exact time required! 


Time To Drain The Reservoir


Here is the question! 

Let T be the capacity of the tank. Let L be the large pipe and S be the small pipe.

T/6L = 12

L = T/72

T/(3L + 9S) = 8

Putting L = T/72,

S = T/108

Hence T/5S = 108/5 gives S = 21.6 hours.



Calculation of Time To Drain The Reservoir

To conclude, small pipes require 21.6 hours i.e. 21 hours and 36 minutes to drain the reservoir.

Journey In Parts

Someone drove from Aardvark to Beeville.

On the first, day they traveled 1/3 of the distance.

On day two, they traveled 1/2 of the remaining distance.

On day three, they traveled 2/3 of the remaining distance.

On day four, after covering 3/4 of the remaining distance, they were still 5 miles away from Beeville.

How many miles had they covered so far?


Distance in Journey In Parts

Know the total distance traveled!
 

Total Distance In The Journey


Click for the question! 

We need to start in reverse.

In last part after covering 3/4 still 5 miles left which accounts for 1/4 of remaining distance. Hence, 20 miles were left at the start of DAY 4.

On DAY 3, 2/3rd covered leaving 20 miles for DAY 4. That means 20 miles distance is remaining 1/3rd. Hence, at the start of DAY 3, 60 miles were left.

On DAY 2, 1/2 of covered leaving 60 miles for DAY 2. So that means 60 miles distance is remaining 1/2. So at the start of DAY 2, 120 miles yet to be covered.

On DAY 1, 1/3 of covered leaving 120 miles for DAY 2. Meaning 120 miles distance is remaining 2/3. Hence, 180 miles yet to be covered at the start of DAY 1.

Out of 180 miles, 175 covered in 4 days still 5 miles left.


Calculation of Total Distance In The Journey

Find The Parking Floor

Six people park their car in an underground parking of a store. 

The store has six floors in all. Each one of them goes to different floor.

Simon stays in the lift for the longest.

Sia gets out before Peter but after Tracy.

The first one to get out is Harold.

Debra leaves after Tracy who gets out at the third floor.

Can you find out who leaves the lift at which floor? 


Find Living Floor Of Each Person
 
Was it really so difficult? 

Finding The Parking Floor


What was the given data? 

The sentence 'The first one to get out is Harold.' suggests that the Harold leaves the lift at the 1st floor.

Similarly, the sentence - 'Simon stays in the lift for the longest.' suggests that Simon leaves he lift at the 6th floor.

Next, sentence - 'Debra leaves after Tracy who gets out at the third floor' suggests Debra leaves the lift at the 3rd floor.

Clearly, the sentence - 'Sia gets out before Peter but after Tracy.' suggests that Sia leaves the lift at the 4th floor.

Also, it is clear that Debra leaves the lift at the 2nd floor and Peter at the 5th floor.



Logic For Finding The Parking Floor

Summary -

Harold leaves at the first floor.


Debra leaves at the second floor.


Tracy leaves at the third floor.


Sia leaves at the fourth floor.


Peter leaves at the fifth floor.


Simon leaves at the sixth floor.