Contaminated pill - One puzzle a day - Puzzle Buddies

You have 5 jars of pills. Each pill weighs 10 gram, except for contaminated pills contained in one jar, where each pill weighs 9 gm. Given a scale, how could you tell which jar had the contaminated pills in just one measurement?

Solution

1. Mark the jars with numbers 1, 2, 3, 4, and 5.
2. Take 1 pill from jar 1, take 2 pills from jar 2, take 3 pills from jar 3, take 4 pills from jar 4 and take 5 pills from jar 5.
3. Put all of them on the scale at once and take the measurement.
4. Now, subtract the measurement from 150 ( 1*10 + 2*10 + 3*10 + 4*10 + 5*10)
5. The result will give you the jar number which has contaminated pill.

Winner:Subodh Singh

Life and Death - One puzzle a day - Puzzle Buddies

Puzzle : One person goes on a trail in a deep forest far away from all the civilization. On the way he gets bitten by a cobra. Luckily the guy has the antidote in his medical kit for cobra bite.

• The antidote is in two bottles - Bottle A and Bottle B
• Each bottle has only 3 pills each
• Both the bottles have similar pills and they are not marked by any sign. It can not be told by looking at pills only if they belong to Bottle A or Bottle B
• The dosage of pills should be as below:
• 1 pill from Bottle A and 1 pill from Bottle B
• After 2 hours again 1 pill from Bottle A and 1 pill from bottle B
• After 3 hours again 1 pill from Bottle A and 1 pill from bottle B

The person in panic tries to take the first dose in a hurry and by mistake takes out 1 pill from bottle A and 2 pills from Bottle B. The pills he takes out falls down on the ground and get mixed. Now he has 3 pills but he can not tell which one is from which bottle.

What should he do to make sure that he takes all the dosages on time?


Solution: Suppose three spilled pills are
Pill 1
Pill 2
Pill 3

Breaks all three pills in halves and takes the doses as below

1. Takes half of Pill 1, half of Pill 2,  half of Pill 3 and half of a new pill from Bottle A.
2. Repeat step 1
3. Take rest of the pills from Bottle A and Bottle B.

Note: Don't forget to visit us again. Answer to the puzzle will be posted tomorrow.

Magic Watch - One puzzle a day - Puzzle Buddies

You are a contestant on a game show. You have three closed doors in front of you. One of the doors has a car behind it and the other two doors have nothing. You have to choose a door to open.

You have with you a Magic Watch.

- Whenever you ask the watch a question with a yes/no answer, it will blink either red or blue.

- One of the colors represents 'yes' and the other 'no'.

- You don't know which color means what. (gotcha!)

- You are allowed to ask the watch only 2 questions before you make your decision.

Which questions would you ask and how would you choose the door to open?

The puzzle might have a number of solutions and this is one of them.

Solution:

The contestant should ask the following two questions:

1) If I asked whether the car was behind door 1, would you blink red?

2) If I asked whether the car was behind door 2, would you blink red?

There are two cases here:

a) red = no, blue = yes:

The watch can answer in 4 different ways:

1) red, blue:

From the answer to the 1st question, car is behind door 1.

From the answer to the 2st question, car is not behind door 2.

2) blue, red:

From the answer to the 1st question, car is not behind door 1.

From the answer to the 2nd question, car is behind door 2.

3) blue, blue:

From the answer to the 1st question, car is not behind door 1.

From the answer to the 2nd question, car is not behind door 2.

4) red, red:

From the answer to the 1st question, car is behind door 1.

From the answer to the 2nd question, car is behind door 2.

b) red = yes, blue = no:

The watch can answer in 4 different ways:

1) red, blue:

From the answer to the 1st question, car is behind door 1.

From the answer to the 2st question, car is not behind door 2.

2) blue, red:

From the answer to the 1st question, car is not behind door 1.

From the answer to the 2nd question, car is behind door 2.

3) blue, blue:

From the answer to the 1st question, car is not behind door 1.

From the answer to the 2nd question, car is not behind door 2.

4) red, red:

From the answer to the 1st question, car is behind door 1.

From the answer to the 2nd question, car is behind door 2.

Observe that the conclusions are exactly the same for the same answer set irrespective of the color code.

Hence, when the watch answers:

1) red, blue: Pick door 1.

2) blue, red: Pick door 2.

3) blue, blue: Pick door 3.

4) red, red: This outcome is impossible since it implies that the car is behind door 1 as well as door 2.

Subodh Singh almost got the answer! Brilliant!

Life of Death - One puzzle a day - Puzzle Buddies

You are a prisoner sentenced to death. The King offers you a chance to live by playing a simple game. He gives you 50 black marbles, 50 white marbles and 2 empty bowls. He then says, "Divide these 100 marbles into these 2 bowls. You can divide them any way you like as long as you use all the marbles. Then I will blindfold you and mix the bowls around. You then can choose one bowl and remove ONE marble. If the marble is WHITE you will live, but if the marble is BLACK... you will die."

How do you divide the marbles up so that you have the greatest probability of choosing a WHITE marble?

Solution: Place 1 white marble in one bowl, and place the rest of the marbles in the other bowl (49 whites, and 50 blacks). This way you begin with a 50/50 chance of choosing the bowl with just one white marble, therefore life!

Vinay is the winner!

Cross The Bridge - One puzzle a day - Puzzle Buddies

Four friends A,B,C,D must cross a bridge in order to reach their camping site.

Its dark in the night and they have only one torch with them.They can not walk on the bridge without the torch.to make the matters worse the bridge can support only a maximum of two persons at any given time.

the time taken by A,B,C,D individually to cross the bridge is given below

A takes 1 min to cross the bridge

B takes 2 min to cross the bridge

C takes 5 min to cross the bridge

D takes 8 min to cross the bridge

if two of them travel together the faster one has to adjust his speed according to the slower one so that they can share the torch.

what is the minimum time taken by them to cross the bridge?

Note: Don't forget to visit us again. Answer to the puzzle will be posted tomorrow.

Solution: Correct answer is given by guru.

First Trip:A+B crosses the bridge and A comes back- Total time taken for this trip =2+1

Second Trip:C+D cross the bridge and B comes back-Total time taken for this trip=8+2

Final Trip :A+B Again -Total time taken for this trip=2

Total time taken for the all of them to cross: 3+10+2= 15

Extra Dollar - One puzzle a day - Puzzle Buddies

Two friends have a dinner together at a restaurant, and the bill is $25
They pay $15 each,which the Waiter gives to the Cashier.The Cashier hands back $5 to the Waiter
The Waiter keeps $3 as a tip and hands back $1 each
So, the friends paid $14 each for the meal, for a total of $28. The Waiter has $3, and that makes $31. Where did the extra dollar come from?

Solution: $25 is sitting with the cashier

$3 is sitting with the waiter

$2 is the change back

Total is $30

$3 tip is part of $28 spent

Winner is Mentor

Camel Racing - One puzzle a day - Puzzle Buddies

There is a wealthy merchant who has two sons. Time has come for him to decide which one of his sons gets his fortune. But first, he wants to find out whether his sons are worthy of his wealth.

He gives each one of them a camel and says:
"You must race the camels to the city of Saria. Whoever's camel reaches there last will get all my wealth."

Now, these two start towards Saria on their camels and are roaming around aimlessly for days as no one wants to reach there first. Luckily for them, a wise dude is passing by. The two sons explain their predicament to him. Upon thinking for a moment or two, the wise dude offers them a solution and they are able to complete their test.

What did the wise dude suggest?

Solution: He told them to switch camels and race to Saria. Subodh Singh is right again!

Two mathematicians - One puzzle a day - Puzzle Buddies

Puzzle: Two mathematicians(old friends) meet after a long time in a bar. The first one tells the other that he got married and has three daughters. The second friend asked about their ages. To make the matter more interesting first one replies, “The product of their ages is 72.” The second mathematician answers, “OK, but that didn’t help a lot.” — “Then I should tell you that the sum of their ages is equal to the street number of this bar.” The second mathematician leaves the bar, returns, and says, “Great, but I still don’t know their age.” The first mathematician smiles and says, “My youngest daughter just started to play piano.” Now the second mathematician knows their ages.

How old are the three daughters? (The age should be thought of as integers only for this problem).

Thanks to Anirban Chatterjee for pointing us to this puzzle.

Solution: There are 3 conditions in this puzzle

1. The product of the ages of three daughters is 72.

2. The sum of all their ages is equal to a number.

3. The youngest daughter just started to play piano.

Let's start with first. There can be only a limited number of ways in which the result of multiplication can be 72.

          OLD        MID        YOUNG       SUM
    72         1           1                 74
    36         2           1                 39
    24         3           1                 28
    18         4           1                 23
    18         2           2                 22
    12         3           2                 17
    12         6           1                 19
     9         8           1                 18
     9         4           2                 15
     8         3           3                 14
     6         6           2                 14
     6         4           3                 13

Now the mathematician knows the number which we do not know in this puzzle but still 

he could not conclude the answer. 

This means that there are two combinations in which the sum is same.

           OLD        MID        YOUNG       SUM
    8         3           3                 14
    6         6           2                 14

Now we have reduced the problem set to two options only.

The third condition says that the younger one just started to play piano,
and that makes it clearer that younger one can not be twin. 
So the the answer is 6,6,2.
Interesting fact here is that now we know the building number also which is 14 :)

Winners: Once again Subodh Singh is the winner.
 Vinay also answered correctly this time.

Move the Digit Math Puzzle - One puzzle a day - Puzzle Buddies

By moving one of the following digits, make the equation correct. 62 - 63 = 1

Solution:2^6-63=1

2 to power of 6 equals 64

Winner: Rajesh Khatri

The Island - One puzzle a day - Puzzle Buddies

100 men were captured and prisoned in an island.the island is guarded by a genie.

Everyday genie takes prisoners out.genie places them in a circle so that everyone can see each other,then all the prisoners are blindfolded. Genie then places hats on prisoners head,some of them are white and some of them are red.their folds will be opened after the genie places hats.

On genie's command the prisoners with white hat should step forward.They will be set free if only the men with white hat steps forward.

If any one without white hat steps forward,genie executes all of them

If no one steps forward,the same game will be repeated the next day,if the game is repeated,each prisoner will get the same hat that they got on the first day

Prisoners are not allowed to communicate with each prisoner.if communicated all of them will be executed.prisoners are not allowed to see the hat that they are wearing

At least one white hat is given, and all prisoners are aware of this.

how many days did it take for the prisoners to get out if genie gave "n" white hats where 1<=n<=100, and how did they do it?

Solution:

Let us say there is one white hat,the answer is simple.the prisoner wearing white hat sees no other white hat and he steps forward.

Now let us take two white hats.No body comes forward on the first day,because the prisoners wearing white hat sees one white hat.On the second day since no body has come forward they both know there must be two white hats and one he can see and other must be his own.so they come forward on second day.

Similarly if there are three white hats they will not come out on second day.it will take three days.

and so on..for "n" it will take n days

the winner is sanal

Note: Don't forget to visit us again. Answer to the puzzle will be posted tomorrow.

Pirates of the Caribbean - One puzzle a day - Puzzle Buddies

Here goes my first puzzle...

There are five pirates. They are arranged by seniority, pirate 5 being the most senior and pirate 1 being the most junior. They have 100 gold coins and need to divide these coins between them.

The pirates follow certain rules to divide the loot. The most senior pirate proposes a solution specifying the number of coins each pirate gets. Then all the pirates, including the one proposing, vote on it(Assuming the proposing pirate votes for himself). If the proposal gets atleast 50% votes, it is accepted. Else, the seniormost pirate is killed and the same procedure is followed with the remaining pirates.

Bear in mind that these are no ordinary pirates. They possess exceptional analytical skills and are well aware of the thought process of all the other pirates in addition to being extremely greedy.

By these rules, since pirate 5 is going to propose a solution first, what should he say so that a) he gets atleast 50% (i.e. 3) votes thus staying alive and b) he gets the maximum possible coins?

Solution: Consider the case where there are only 2 pirates. This is what pirate 2 proposes:

Pirate 2: 100

Pirate 1: 0

He votes for himself and stays alive.

If there are 3 pirates, this is what pirate 3 proposes:

Pirate 3: 99

Pirate 2: 0

Pirate 1: 1

Pirate 1 thinks that 1 coin is better than 0(which is what he will get if pirate 2 is in charge) and votes in favour. Pirate 3 gets 2 votes and stays alive.

With 4 pirates, this is what pirate 4 proposes:

Pirate 4: 99

Pirate 3: 0

Pirate 2: 1

Pirate 1: 0

Pirate 2 thinks that 1 coin is better than 0(which is what he will get if pirate 3 is in charge) and votes in favour. Pirate 4 gets 2 votes and stays alive.

With 5 pirates, this is what pirate 5 proposes:

Pirate 5: 98

Pirate 4: 0

Pirate 3: 1

Pirate 2: 0

Pirate 1: 1

Pirates 3 and 1 think that 1 coin is better than 0(which is what they will get if pirate 4 is in charge) and vote in favour. Pirate 5 gets 3 votes and stays alive.

Subodh Singh provided the correct solution. Two in a row!!

Note: Don't forget to visit us again. Answer to the puzzle will be posted tomorrow.

Man with a car - One puzzle a day - Puzzle Buddies

Puzzle: A man is driving a car with only two seats on a rainy day. As he passes a bus stop he notices that three people he know are standing there getting soaking wet:

1. His best friend

2. His grand mother - who needs immediate medical attention

3. His girlfriend

The guy has to stop at that bus stop and some how please all three and himself also. 

The question here is what will he do so that every one is happy.


Solution: I liked the comments of Austin though the correct answer is provided by Subodh Singh.
The correct solution is that the guy will give his car to his best friend and will ask him to take his grand mother to the hospital. He will stay back with his girl friend and pretend that he can even withstand heavy rain with her :). Comments are still welcome.


Please provide your answers under comments section

Note: Don't forget to visit us again. Answer to the puzzle will be posted tomorrow.