I am white when I am dirty, and black when I am clean. What am I?

What is so fragile that saying its name breaks it?

Why 1729 is a magic number? Answer Logically.

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

There are a hundred statements.

First person says: At least one of the statements is false.

Second person says: At least two of the statements is false.

Third person says: At least three of the statements are false.

Fourth person says: At least four of the statements are false.

..

..

..

Hundredth person says: At least a hundred of the statements are false.

Analysing it, how many statements do you think are false and how many are true?

Which tank will fill first?

How many times can you subtract the number 5 from 25?