• Views : 50k+
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Mind Teasers : Is This Proof Correct Problem

Difficulty Popularity

p = 9.999999...
10p = 99.999999...
10p - p = 90
9p = 90
p = 10

In the proof above, you can find out how 10 is equal to 9.999999... .

Is this proof correct?

Does 10 equals 9.99999 for real or there is some error in the proof?

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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 : Two Men One Question Puzzle

Difficulty Popularity

Imagine that you are travelling to a village. You happen to reach a point in the road where there is a fork. There are two ways that you can go into but only one amongst them is correct and leads to the village. You happen to see two men standing on the fork and you can ask them for the direction. To your bad luck, one amongst the two men always lies and the other one always says the truth. But you do not know who is a liar and who is not. At that point of the situation you are allowed to ask only one question to any one of the men standing there.

What question will you ask?

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

Mind Teasers : Popular Castle History Puzzle

Difficulty Popularity

A square island comprised of a square castle. A 14m wide trench surrounded the island from everywhere. Roman Empire wanted to invade the castle and gain the loot as well as possession of the island. They brought along wooden planks to cross the trench. However, they realized that the planks were just 13m long.

How did they use those planks to invade as well as capture the island ?

  • Views : 90k+
  • Sol Viewed : 30k+

Mind Teasers : Homicide Detective Puzzle

Difficulty Popularity

A homicide detective is called at a crime scene. A man is lying dead in front of the building and seeking the position of the windows on the building and the position in which the body is lying, it is evident that the man jumped out from one of them and committed suicide.

The detective asks his team to collect the traces if they can find any on the body and heads towards the building. He goes to the first floor and towards the room that is on the front side. Inside the room, he lights a cigarette, walks towards the window facing the dead body, opens the window and throws out the cigarette. He then goes to the second floor and repeats the same process.

He keeps doing the same thing till he is done with all the floors and then takes the lift to the ground floor. Upon reaching there, he informs the team that it is not a suicide but a murder.

While the whole team is shocked to hear the revelation, he lights another cigarette and takes a hard puff.

How do you think he found out that it was a not a suicide?

  • 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 : 70k+
  • Sol Viewed : 20k+

Mind Teasers : Famous Water Jug Problem

Difficulty Popularity

You live in Dubai and had an infinite supply of oil and a 5 liters and 3 liters jar,
how would you measure exactly 4 liters (of-course in minimum numbers of step) ?

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

Mind Teasers : Harry Potter And Prisonor of Azkaban Riddle

Difficulty Popularity

Think of a person living in a disguise
The one who also deals in secrets and speaks nothing other than lies
Now think of a thing that's always the last to mend
What's the middle of the middle and also the end of the end?
Now think of the sound that you have often heard
When you were searching for a difficult-to-find word
Now if you can join them together and you can answer this
Which creature would you be reluctant to kiss?

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

Mind Teasers : Dirt Hole Tricky Riddle

Difficulty Popularity

How many cubic meters of dirt are in a hole of 20 meter long and 30 meter wide.

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

Mind Teasers : Tough Number Problem Riddle

Difficulty Popularity

Find smallest number that you can write using all the vowels(A,E,O,I,U) exactly once?

  • Views : 90k+
  • Sol Viewed : 30k+

Mind Teasers : Popular Thinking Puzzle

Difficulty Popularity

Once there lived a king who did not allow anybody to leave the kingdom and any foreigners in his kingdom. There was only one bridge that connected his empire with the outer world. A guard who was a sharpshooter was specially assigned for a lookout on the bridge. According to the orders, anyone moving outside should be killed and anyone coming to his kingdom should be sent back. To take rest, the guard used to sit inside his hut for 5 minutes and return back on the lookout. The bridge took a minimum of 8 minutes to pass.

Even then, a woman was able to escape the kingdom without incurring any kind of harm to the guard.

How ?

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