#11 - HubSpot Interview Puzzle

In a family supper, a grandfather, a grandmother, two fathers, two mothers, four children, three grandchildren, one brother, two sisters, two sons, two daughters, one daughter in law, and one mother in law need to sit at a table.

There are only seven chairs available at the place. How many more chairs do they have to borrow so that everyone can sit down together for the suppers if everybody requires a separate chair?

HubSpot Interview Puzzle
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No other chair is required as there are only seven people:
A Grandfather married to Grandmother.
They have a son who is married to a woman.
Together, they have three children - One son and two daughters.

These are the only seven people

#12 - Fun Maths Riddle

There are four numbers given to you: 2, 3, 4 and 5. You are allowed to use only two mathematical symbols: + and = and come up with a mathematically true equation.

Can you do it?

PS- You can't repeat the symbols or numbers.

Fun Maths Riddle
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3^2 = 4 + 5
(^ is used for squaring the term, it is not a mathematical symbol.)

#13 - Easy Murderer Mystery Riddle

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

Easy Murderer Mystery Riddle
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It is clear that the police never told him where the crime scene was. But still he reached the correct place. It means that he knew about the crime and he himself is the murderer.

#14 - BlackRock Interview Puzzle

In a party, there are five people and a whole round cake lying at the center of table. Only four people will make a cut and take their piece and the last one will get the remaining piece on the table. How can they make sure that everyone gets a 1/5th of piece?

BlackRock Interview Puzzle
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Please refer to the picture. If the four people cut along with the line, everyone will get an equal piece.

#15 - Tricky Fun Riddle

Do you know who was buried in Drake's tomb?

Tricky Fun Riddle
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Drake obviously

#16 - Hard Maths Cube Riddle

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.

How many remain now?

Hard Maths Cube Riddle
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512
A layer will mean to remove from all sides of the cube. Thus it would reduce the dimension be two not one. In this way only a cube of 8x8x8 will remain. This totals to be 512.

#17 - Tricky Picture Puzzle

In the picture given with this question you will find a square piece of a paper with a hole that is denoted by the circle on the top right side.You have to cut the paper in a manner that it forms two and only two separate pieces of paper and then rearrange the pieces in a manner that the holes comes in the center of the paper.Can you do it?

Tricky Picture Puzzle
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The first image in this answer clarifies where to make the cut to divide the paper into two separate pieces. The second image is the rearranged position if you rotate the right piece of paper to 180 degrees. In this manner, the hole is now in the center.

#18 - Decode Text Riddle

If in a code language, DISTANCE is written as IDTUBECN and DOCUMENT is written as ODDVNTNE, the how will THURSDAY be coded as in the same language?

Decode Text Riddle
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HTVSTYAD

DISTANCE = IDTUBECN
D and I are interchanged in position.
S, T and A are added with one position to form T, U, B respectively.
N, C and E are written in opposite order.

Thus in the same manner
THURSDAY= HTVSTYAD.

#19 - Trick Math Problem

While boarding a bus you notice that there are 7 girls in the bus already. All the girls have 7 bags each. In each bag there are 7 adult cats. Each of the adult cat have 7 little one. Each of the cat has 4 legs.

Can you calculate the number of legs in the bus?

Trick Math Problem
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Every girl has seven bags comprising of seven adult cats each with seven little cats per adult cat.
Thus for one girl:
1 girl + 49 adult cats + 343 little cats
Since there are 7 girls:
7 girls + 343 adult cats + 2410 little cats

Now calculating the legs:
14 legs of girls + 10976 legs of cats (There are total 2744 cats with 4 legs each).
Thus total legs = 10990

Now I climbed aboard the bus as well, thus total number of legs = 10990 + 2 = 10992 legs
If we add two legs of the driver as well,
Total legs = 10992 + 2 = 10994

#20 - Infosys Interview Puzzle

The king of Octopuses has servants who have six, seven or eight legs. The distinguishing characteristics of the servants is that the one with seven legs always lie but the one with either six or eight legs speak the truth always.

On a certain night, four servants meet and converse:
The black one says, 'We have 28 legs altogether.'
The green one says, 'We have 27 legs altogether.'
The yellow one says, 'We have 26 legs altogether.'
The red one says, 'We have 25 legs altogether.'

Can you identify the color of the servant who is speaking the truth?

Infosys Interview Puzzle
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The green servant is telling the truth.

To prove it, let us first assume that one of them is telling the truth. It is obvious that three of the four servants are lying as they are disagreeing with each other.

Suppose if the black servant is telling the truth. In that case, the black one is having either 6 or 8 legs. And each of the other octopus is lying will then have 7 legs. In this case, the total number of legs will be 6 + 7 + 7 + 7 = 27 legs or 8 + 7 + 7 + 7 = 29 legs. But the black servant said that they have 28 legs all together. Thus he is lying.

Now follow the same logic with the remaining three servants as well assuming all of them truthful one by one. You will realize that only the Green octopus is telling the truth.