Guess the number II solution

The numbers in this puzzle follow the below pattern:

       result = num*6 + 6 or (num+1) * 6.

For example
3*6 + 6 = 24

Hence for 9 the result will be 9*6 + 6 = 60.
So correct answer is 60.

Guess the number II

In the below pattern guess the missing number


                                           12  78
                                            5   36
                                            3   24
                                            9    ?

Click here for the solution   

                                         

Guess the number solution

The pattern is a bit tricky but easy to crack.
Missing number will be 4

The pattern followed is that the sum of two numbers is used to create the upper row.
Example
9+8 = 17 so last digit is 7.
next 8+6 = 14 . Here last digit is 4 and so on.

Hence the correct solution will be 4.

Guess the number

In the below pattern guess the missing number


                                                            ?
                                                        1     3
                                                     7    4     9
                                                  9    8     6    3


Click here for the solution  

Worker Salary Puzzle Solution

We can pay the worker by doing 2 cuts in the chain.

Cut should be such that it divides the chain in the ratio of 4:2:1.

Let us say these pieces are 4x,2x and 1x.

For example - Let us say the chain length is 7 cm. Then make 2 cuts and get 3 pieces of the chain i.e 4 cm,2 cm and 1 cm.

Now the salary will be given to worker as :

Day 1 - Give him 1x cut.

Day 2 - Give him 2x cut and take back 1x cut.

Day 3 - Give him 1x cut.

Day 4 - Give him 4x cut and take back 1x and 2x cut.

Day 5 - Give him 1x cut.

Day 6 - Give him 2x cut and take back 1x cut.

Day 7 - Give him 1x cut.

This way we can pay the worker for 7 days.

Worker Salary Puzzle

You have a metallic chain which has to be paid to a worker for working for 7 days.
You can cut the chain and can pay the worker each day for the work done.
What is the minimum number of cuts required in the chain for paying the worker.

Click here for the solution.

Rotating disc puzzle solution

We can deduce the rotation of the disc with 2 sensors by placing them at an angle of 90 degree.
Let us say we have 2 sensors named A and B.

Now there are two possible initial values of the sensor. Either Black or White.
Let us assume that Black - 0 and White - 1

The disc is rotating clockwise if Sensor A changes to the value of Sensor B and Sensor B becomes Sensor A XOR 1

The disc is rotating counter clockwise if Sensor A changes to the value of Sensor B XOR 1 and Sensor B becomes Sensor A.

This is explained with the below table.

Initial	Clockwise	Counter-Clockwise
A - Black B - Black	A - Black B - White	A - White B - Black
A - Black B - White	A - White B - White	A - Black B - Black
A - White B - Black	A - Black B - Black	A - White B - White
A - White B - White	A - White B - Black	A - Black B - White

Rotating Disc Puzzle

You are given a disc.
One half of the disc is painted black and other half of the disc is white.
You are provided with camera sensors which can predict the color of the disc.
Sensors will indicate the color of the disc.
Find the minimum number of sensors required for to find the direction of the moving disc.

Click here for the solution.

Even and Odd number stream puzzle Solution

To determine whether a 32 bit number is even or odd we need to check the LSB of that number.
If least significant bit of the number is 0 then it is even otherwise it is odd.

So in the incoming 32 bit numbers we just have to check the Least significant bit of the number and we should be able to check the same.

This is the most optimal solution in terms of hardware design or software compilation.

Even and Odd number stream puzzle

A sequence of 32 bit numbers arrive in order. Design a logic to check for even and odd numbers in this sequence and let the user know the same.
Logic should be most optimal and should work in every case.

Click here for the solution.

Camel Banana Puzzle Solution

 The camel can carry at most 1000 bananas and there are 3000 bananas to be carried.

      Let us consider that x trips are needed to carry all the bananas from the starting point S to the place X. The place X is not the market. As the camel eats a banana for each kilometer it travels, so that it cannot travel more than 500 kilometer. Therefore the place X lies between the start point and the market. After bringing all the bananas to the place X, consider another place Y which takes less than x trips, from X to Y. After reaching the place Y, it will take one trip to the market M.
      The camel should carry exactly 2000 bananas from the place X. So we can calculate the distance of SX as 3000 - 5 x SX = 2000, therefore SX = 200 kilometers. Calculate as such for the distance XY, 2000 - 3 x XY = 1000, so XY = 333 1/3. As the both distances are less than 500, the camel can travel back from X to S and Y to X. Therefore the distance BM will be 1000 - 200 - 333 1/3 = 466 2/3.
      Now lets start from the first. Initially the camel take 1000 bananas from the Start point S to the place X at a distance of 200 kilometers. Drops 600 bananas and takes 200 bananas. Then it takes 1000 bananas from P to X and drops 600 bananas, taking 200 bananas. At last it takes 1000 bananas to the place X and drops 800 bananas. There are 2000 bananas at the place X.
      Now the travel from the place X to Y, which is 333 1/3 kilometers. First it takes 1000 bananas from X to Y, drops 333 1/3 and takes 333 1/3 to X. At last it takes 1000 bananas from X and drops 666 2/3. Totally the place Y will have 1000 bananas.
      The final voyage to the market M from Y, where the distance is 466 2/3. It takes 1000 bananas and reach the market with 533 1/3 bananas.

So he will reach the market with 533 bananas.

The basic approach here is to divide the distance in such a way that camel can come back to the start point and maximum number of bananas are present at the mid point.

Camel Banana Puzzle

I came across this new puzzle asked by an Investment Bank in one of the interviews.

A farmer has 3000 bananas which he wants to transfer to a market 1000 km away from his house.

He has a Camel which can carry 1000 bananas at a time but the camel eats one banana for every kilometre he travels.

How many maximum bananas can the farmer take to the market.

Click here for the solution.

1 Rupee Puzzle Solution

Well the trick is in the puzzle itself and you should read it twice thrice to understand it.

When they pay 10 rupees each to the waiter they had given 30 rupees in total.

When waiter returns 5 rupees to them they have paid 25 rupees to the cashier.

Now the waiter return them 3 rupees so they have paid 25 rupees to the cashier and 2 rupees to the waiter.

so in total 25+ 3 +2 =30 rupees.

and the amount paid in restaurant is 25(cashier) + 2(waiter) = 27 = 3 x 9. So they pay 9 rupees each for the meal and got 1 rupee back.

1 Rupee Puzzle

This is one of the tricky puzzles asked in interviews.

Three friends go for a lunch at a restaurant. The bill for the lunch is 25 rupees. They all pay 10 rupees each and the waiter took the money to the cashier.

The cashier deducted the amount and gave 5 rupees to the waiter. But the waiter was not able to split the money among the three friends so he keeps 2 rupees as a tip and give 1 rupee each to the friends.

Now :

They all paid 10 rupees and got 1 back so actual money paid by them = Rs 9
They were 3 friends so total money paid by them will be = Rs 27
Waiter keeps 2 rupees as a tip so total = 27 + 2 =29

So where did the one rupee go?

Click here for the Solution

Number of Girls Puzzle Solution

Well this is a simple probability puzzle and most of the time people answer this puzzle correctly.

Let the number of couples in the country be X. So there will be X boys in the country as each couple will have one boy.

So probability of a girl child will be = 1* probability of one girl + 2* probability of two girls + 3 * probability of three girls + ...

number of girls = 0 + 1 x (0.5 x 0.5 x X) + 2 x (0.5 x 0.5 x 0.5 x X) + 3 x (0.5 x 0.5 x 0.5 x 0.5 x X) + number of girls = 0 + X/4 + X/4 + 3X/8 + .......

So if you solve this equation will approximation you will get
number of girls = X

So Ratio = 1:1

and the researcher is right as the ratio of girls to boys in the country will be same.

Number of Girls Puzzle

This puzzles is one of the classic probability puzzle asked in most of the interviews.

There is a country A where every family wants a boy. So each family continues having babies till they have a boy in their family.

This issue was raised to the health authority of the country but the head of the health department told that this is good as advised by one of our mathematician researcher in our department.

So how is this condition good and what is the ratio of boys to girls in the country.

Assume that the probability of having a girl or a boy is same.

Click here for the solution

Heaven or Hell Puzzle Solution

You have to think a bit for this puzzle.

the question is
If I asked the other gatekeeper which door leads to heaven, what would he tell me?

The door that the gatekeeper tells will be the one that leads to hell as if it is the gatekeeper who speaks truth he will tell the truth and the other gatekeeper will lie so you will get the door which will lead you to hell.

If it is the gatekeeper who speaks lie he will tell lie by telling you the door which goes to hell.

So ultimately you will get the door which goes to hell if you ask this question to any of the guards.

Heaven or Hell Puzzle

This is one of the classic puzzles asked in interviews nowadays.

You are standing before two doors.One door leads to the heaven and the other leads to Hell but you don't know what hides behind the doors. There are two gatekeepers. You know one of them always tells the truth and the other always lies, but you don't know who is the honest one and who is the liar.

You can only ask one question to one of them in order to find the way to heaven. What is the question?

Click here for the solution

Three Friends Puzzle Solution

In this puzzle we have to make sure that no person is in danger.

Let the names of the persons be A, B and C.

So they start from their starting point and after 1st day A give it's 2 days resource to B and C. So A has 1 day resource left with him which he can use to return back to the starting point. Now B and C starts again and they have a 4 day supply again because of the food and water given by A.

After the second day B gives his 1 day supply to C and keeps the remaining 2 days supply with him so that he can return safely to the starting point.

Now after 2nd day C again has 4 days supply so he can continue towards the destination point and will reach there safely.

So only 1 person can reach the destination safely.

Images:

A - 4 days                                                                                                                  A - 3 days
B - 4 days  ----------------------------------------------------------------------------------- B - 3 days
C - 4 days                                           after 1st day                                                  C - 3days

A gave its 2 days supply to B and C. So now

A - 1 day                                                                                                                                
B - 4 days  ---------------------------------------------------------------------------------- B - 3 days
C - 4 days                                           after 2nd day                                                 C - 3days

B gave it's 1 day supply to C and B returns back.
B - 2 days
C - 4 days

So C has 4 days resources and can cover the 4 remaining days.

Three Friends Puzzle

This puzzles is used to test the management capability of the student by the interviewers.

Three Friends starts on a trip to the Sahara Desert. It takes 6 days to reach the destination. Each person can carry only enough food and water for 4 days. So the maximum resource which a person can carry will last for 4 days.

There is no place in between the trip where they can refill their resources.

Without risking anyone's life they have to make as many people as possible to safely reach the destination. How many people can safely reach the destination.?

Click here for the solution