What is black when you buy it, red when you use it, and gray when you throw it away?

Why is a river so rich ?

Can you find out which options fits best with the missing column?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

You have a square. What you have to do is cut and reassemble the square such that you create a Red Cross sign that has the same volume as that of the square.

If 2 workers can complete painting 2 walls in exactly 2 hours.

How many workers would be needed to paint 18 walls in 6 hours?

The richest man in the city Mr Rechard is kidnapped. James Bond is appointed to the case. At the crime scene, a note is found written by Mr Richard. The note read:

"First of January, Fourth of October, Fifth of March, Third of June."

James Bond knew that somehow, the killer's name was hidden in the note. The following were the suspects:

Jack Richard, the son and the heir of property.
John Jacobson, the employee of Richard.
June Richard, the wife of Richard.

James Bond took only a few moments to deduce the killer's name. Can you tell who was the killer?

Can you solve below mathematical equation?

2^1234 - 2^1233

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

Solve this riddle by finding the odd one out from the rest.