How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

A train full of passengers goes through a tunnel. When the train comes out from the other end, there is no single person on the train.

How did it happen?

What breaks yet never falls, and what falls yet never breaks?

You stand in front of two doors. A guard stands next to each door. You know the following things: one path leads to paradise, the other leads to death. You cannot distinguish between the two doors. You also know that one of the two guards always tells the truth and the other always lies. You have permission to ask one guard one question to discover which door leads to paradise. What one question would you ask to guarantee you enter the door to paradise?

Can you replace the question mark with the correct number in the below table sequence?

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?

You need to remove two matchsticks to make the below equation true. Can you do it ?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

In the four images below, can you find the odd one out?

In the image below, you can see two glasses and two matchsticks.You need to move four matchsticks in such a manner that the crosses come inside the glasses. Note: you cannot move the crossed.