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

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Asked by Neha on 30 May 2024


There is an ancient kingdom where every married woman keeps information regarding the fidelity of other men. However, what they don't know is the fidelity of their own husbands. Also, there is an ancient belief that they don't tell each other about the fidelity of their husbands.

On a certain day, the queen of the kingdom declares that she has identified at least one unfaithful man in the kingdom. She allows the wives to identify and gives them authority to kill their husbands if they are unfaithful at midnight.

How will the wives manage it?

Asked by Neha on 03 Oct 2023

There is a circular car race track of 10km. There are two cars, Car A and Car B. And they are at the exact opposite end to each other. At Time T(0), Both cars move toward each other at a constant speed of 100 m/seconds. As we know both cars are at the same speed they will always be the exact opposite to each other.
Note, at the center, there is a bug which starts flying towards Car A at time T(0). When the bug reaches car B, it turns back and starts moving towards the car A. The speed of bug is 1m/second. After 5 hours all three stop moving.
What is the total distance covered by the bug?

Asked by Neha on 03 Aug 2023


Keyboard words are not in alphabetical order, Why?

Asked by Neha on 26 Jul 2023

I’m tall when I’m young, and I’m short when I’m old. What am I?

Asked by Neha on 07 May 2022

John and his wife were living in a rural place. On a particular day, John's wife fell ill and he called the local doctor. When the doctor picked up, he said, "Doctor, my wife is ill. She might have appendicitis."

"This can't be possible! I took out her appendix two years ago myself," the doctor explained.

When diagnosed, John's wife was found to have appendicitis. How can this be possible?

Asked by Neha on 19 Jun 2024


I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

Asked by Neha on 23 Nov 2025

Two men play a dice game involving roll of two standard dice. Man X says that a 12 will be rolled first. Man Y says that two consecutive 7s will be rolled first. The men keep rolling until one of them wins.

What is the probability that X will win ?

Asked by Neha on 13 Apr 2023

A few friends are enjoying their sea voyage in a boat full of apples. On the way, they felt hungry and thus decided to eat the apples. Together, they ate two dozen of apples. When they have eaten the apples, will there be any change in the water level?

Asked by Neha on 06 May 2021


I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

Asked by Neha on 23 Mar 2022

Hot Articles

Amazing Facts

Rubik’s Cube

The inventor of the Rubik’s Cube didn’t realize he’d built a puzzle until he scrambled it the first time and tried to restore it.