Unlisted Phone Number

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?




Similar Riddles

Mr Black, Mr Gray, and Mr White are fighting in a truel. They each get a gun and take turns shooting at each other until only one person is left. Mr Black, who hits his shot 1/3 of the time, gets to shoot first. Mr Gray, who hits his shot 2/3 of the time, gets to shoot next, assuming he is still alive. Mr White, who hits his shot all the time, shoots next, assuming he is also alive. The cycle repeats. If you are Mr Black, where should you shoot first for the highest chance of survival?

Asked by Neha on 18 Feb 2025


The captain of a ship was telling this interesting story: "We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly." How can that be possible?

Asked by Neha on 26 Mar 2024

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

Game of Chess

Asked by Neha on 14 Nov 2023


What you cannot hold but it is yours?

Asked by Neha on 28 Dec 2024

I don't get anymore wetter, no matter how much rain falls on me.

Asked by Neha on 22 Jan 2025

Bay of Bengal is in which state?

Bay of Bengal

Asked by Neha on 12 Mar 2021


Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

Asked by Neha on 23 Oct 2025

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

Asked by Neha on 19 Mar 2025

Intelligence Agency need to break the vault but the problem is that they are not able to break the vault.

On the vault, a text is written as:

31 11 33 33 43 45
21 25
31 24 11 31 51 41

To Break the code Intelligence Agency brings a mathematician named Joseph.
Minutes later he deciphers the code.

Whats the code?

Asked by Neha on 14 May 2021


Rectify the following equality 101 - 102 = 1 by moving just one digit.

Mathematical Signs Magic

Asked by Neha on 08 Mar 2021

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Amazing Facts

Out of the Box

The phrase “thinking outside the box” was popularised from the solution to a topographical puzzle involving 9 dots in a box shape.