An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

I cannot talk, but I always reply when spoken to. What am I?

In the following picture, E is going to slide the object down and as per the terrain and the physics, the round object is going to travel all the way till the end. Now, can you analyze who all people will die when it happens?

It is always ahead of me yet I can never see it. What is it?

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

How many sides does a circle have?

Replace the question mark with the number below given a simple math problem.

Rectify the following equality 101 - 102 = 1 by moving just one digit.