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Mind Teasers : Extremely Hard Civil Services Problem

Difficulty Popularity

( ) + ( ) + ( ) + ( ) + ( ) = 30
This is what you have for equation. The following are the numbers that you can use to fill in the brackets:
1, 3, 5, 7, 9, 11, 13 and 15

You can repeat the numbers if required. The resulting sum should be 30.

This question appeared in the UPSC final examination in December 2013. Out of all the people who appeared, only one guy was able to solve this namely Gaurav Agarwal.

Can you solve it?

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By Admin
  • Views : 40k+
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Mind Teasers : River Crossing Brain Teaser

Difficulty Popularity

River Thames needs to be crossed by Mr. Father, Mrs. Mother, A Thug, A Policeman, 2 dogs and 2 Cats. There is only one boat, which can carry only two people (or a person and an animal or two animals) at a time. Only the humans (excluding the thug) know how to operate the boat. The boat must travel back and forth across the river in order to pick up all of the people and animals.
Following rules must be followed at all times:
Mr. Father: Mr. Father cannot stay with any of the cats, without Mrs. Mother's presence.
Mrs. Mother: Mrs. Mother cannot stay with any of the dogs, without Mr. Father's presence.
Thug: The thug cannot stay with anyone, if the policeman is not there.
Policeman Allowed to travel with everyone.
2 Dogs, 2 Cats: Not allowed to travel without a human, or be in the presence of the thug without the policeman's supervision.
The dogs are not allowed to be in the presence of Mrs. Mother without the supervision of Mr. Father.
Similarly, The cats are not allowed to be in the presence of Mr. Father without the supervision of Mrs. Mother.
Both the dogs and cats are allowed to be unsupervised (provided the other rules are satisfied.)
How will everyone get to the other side of the river Thames? None of the rule can be broken, and all rules apply on the boat as well as on the land.

  • Views : 80k+
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Mind Teasers : Intel Logical Interview Problem

Difficulty Popularity

Chanu bought an ice cream cone having 5 different flavor scoop.
The five flavors in random order are Jamaica, nutty-chocolate, peppermint, walnut and orange

These are some hints to help identify the puzzled reader to determine the order of flavor from top to bottom.
1. The bottom flavor of the cone has 7 letters.
2. The walnut scoop is at between Jamaica and the nutty-chocolate scoop.
3. walnut is above the orange scoop but below the nutty-chocolate scoop.

So can you figure out the flavor of ice cream in order from top to bottom?

  • Views : 70k+
  • Sol Viewed : 20k+

Mind Teasers : Tricky Probabilty Problem To Solve

Difficulty Popularity

Aishwarya was first to board to her flight to delhi.
She forgot her seat number and picks a random seat for herself.
After this, every single person who get to the flight sits on his seat if its available else chooses any available seat at random.
Abhishek is last to enter the flight and at that moment 99/100 seats were occupied.

Whats the probability what Abhishek gets to sit in his own seat ?

  • Views : 40k+
  • Sol Viewed : 10k+

Mind Teasers : Draw Direction Problem

Difficulty Popularity

B is to the North-East of D; A is to the North-East of C; C is to the West of D; E is to the South-West of D and to the South of C; and A is to the north of D and in line with B.

Can you find out in which direction of E is B located?

  • Views : 40k+
  • Sol Viewed : 10k+

Mind Teasers : Difficult Brain Twister

Difficulty Popularity

A strange tradition is followed in an orthodox and undeveloped village. The chief of the village collects taxes from all the males of the village yearly. But it is the method of taking taxes that is interesting.

The taxes paid in the form of grains and every male should pay equal pounds corresponding to his age. In simpler terms, a man aged 10 years will have to pay 10 pounds of grains and a 20 years old will be paying 20 pounds of grain.

The chief stands on a riser containing 7 different weights next to a large 2 pan scale. As per the interesting custom, the chief can only weigh using three of the seven weights.

In such a scenario, can you calculate what must be the weights of the seven weights each and who is the oldest man the chief can measure using those weights?

  • Views : 80k+
  • Sol Viewed : 20k+

Mind Teasers : Playing Cards Puzzle

Difficulty Popularity

I purchased five decks of card from the market and mixed them.
Now i have ( 5 * 52 = 260 cards).

What is minimum number of cards, i need to take out from the above 260 cards to guarantee at least one 'four of a kind'.

  • Views : 50k+
  • Sol Viewed : 20k+

Mind Teasers : Fake Coin Brain Teaser

Difficulty Popularity

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

  • Views : 70k+
  • Sol Viewed : 20k+

Mind Teasers : Tricky Math Race Riddle

Difficulty Popularity

Rooney, Hernandez, and Robin race each other in a 100 meters race. All of them run at a constant speed throughout the race.

Rooney beats Hernandez by 20 meters.
Hernandez beats Robin by 20 meters.

How many meters does Rooney beat Robin by ?

  • Views : 60k+
  • Sol Viewed : 20k+

Mind Teasers : Guard Door Riddle

Difficulty Popularity

You are in a strange place which is guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there.
What should you ask?

By Admin
  • Views : 50k+
  • Sol Viewed : 20k+

Mind Teasers : The Hundred Number Puzzle

Difficulty Popularity

We can create number 100 by using all numbers, i.e.0123456789 and mathematical operators (+/-) in many ways.
Example
98 + 7 + 6 - 5 - 4 - 3 + 2 - 1 = 100

But if we add a condition that the use of the number 21 is the must. Then there are only a few solutions.

One of such solution is:
98 - 7 - 6 - 5 - 4 + 3 + 21 = 100

Can you tell any other solution?

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