What is the word or phrase?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

The husband and wife were jogging in the morning. To match every two steps of the husband, the wife required three steps. If Both of them start with the here right foot. After how many steps do their left foot be together?

Move four matchsticks to the below square to form three squares?

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Spot what is wrong here in below Picture?

The cream is heavier than Milk. True or False?

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?