• Views : 50k+
  • Sol Viewed : 20k+

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?

Discussion
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  • 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 : Inspector Montalbano Mystery Puzzle

Difficulty Popularity

Before going to work, Inspector Montalbano got into the fight with his wife. After coming back from the work he found out that the police was in the home and his wife had just killed a burglar.
The police told that she killed the burglar in self-defense. She told her husband the story that she heard a doorbell and thought that it was me and as soon as she opened the door, the burglar jumped into her and she was so scared that she killed burglar immediately with the knife. Inspector Montalbano asked the police to arrest her wife for murder conspiracy. Why?

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

Mind Teasers : New Answer Riddle

Difficulty Popularity

There is a puzzle which can be asked all day with a different correct answer each time. What is the puzzle ?

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

Mind Teasers : Hard Chess Puzzle Problem

Difficulty Popularity

Your pieces are white.
You need to win in half a move.

How can you do this ?


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

Mind Teasers : Murder Mystery Puzzle

Difficulty Popularity

One evening there was a murder in the home of married couple, their son and daughter. One of these four people murdered one of the others. One of the members of the family witnessed the crime.

The other one helped the murderer.

These are the things we know for sure:

1. The witness and the one who helped the murderer were not of the same sex.

2. The oldest person and the witness were not of the same sex.

3. The youngest person and the victim were not of the same sex.

4. The one who helped the murderer was older than the victim.

5. The father was the oldest member of the family.

6. The murderer was not the youngest member of the family.

Who was the murderer?

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

Mind Teasers : Quick Thinking Maths Problem

Difficulty Popularity

A petri dish kept in a lab has a colony of healthy bacteria. Every bacterium divides itself into two in exactly two minutes. Now the colony started with a single cell at 2 pm. If the petri dish was exactly half full of bacteria at 3 pm, when will the dish become full of bacteria?

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

Mind Teasers : Terrorist Plane Hijack Puzzle

Difficulty Popularity

A terrorist hijacks a plane with 10 passengers and there is lots of gold in the plane.
After talking the gold , he asked the government officials for 11 parachutes.
He killed all the passenger so that no one can identify him , take one parachute and jumps off.

Was he stupid to ask for 11
parachutes if he need only one ?

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

Mind Teasers : Tough Two Jug Measuring Puzzle

Difficulty Popularity

I got two jugs of
A) 11 liter
B) 6 liter

How can I measure exactly 9 liters ?

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

Mind Teasers : Logical Bank Brain Teaser

Difficulty Popularity

A bank customer had Rs.100 in his account. He then made 6 withdrawals, totaling Rs.. He kept a record of these withdrawals, and the balance remaining in the account, as follows:

Withdrawals Balance left
Rs.50 Rs.50
Rs.25 Rs.25
Rs.10 Rs.15
Rs.8 Rs.7
Rs.5 Rs.2
Rs.2 Rs.0
Rs.100 Rs.99


Why are the Totals not exactly right ?

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

Mind Teasers : NewsPaper Riddle

Difficulty Popularity

A newspaper is supposed to have 60 pages.Pages 14 and 21 are missing from the newspaper.

Can you tell me , Which other pages won't be there as well ?

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