Buy me, smell me or deliver me, I do not change.

Who am I?

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

Can you solve the maths in the below-given picture equation?

A boy was locked in a room by some robbers. All that is in the room is a piano, a calendar, and a bed. The room is locked from the outside. What does he eat, drink, and how does he escape and get out?

Whats the next number in the below number sequence pattern.

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

What seven-letter word has hundreds of letters in it?

You have an empty wine bottle with a cork that has been secured at the top in a normal way. There is a metal ring inside the bottle that is suspended by a string.

How can you make the metal ring drop to the bottom if you are not allowed to touch anything - not the bottle, not the cork, not the thread and not the ring?

In an Art Gallary, When the clock hit 11 am, Artist hung the painting number 30. When it struck 4 pm, he hung painting number 240 and when it struck 7:30 pm, he hung painting number 315.

Can you determine, which painting number will he hang when the time is 9:20 pm?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?