What always comes into a house through the keyhole?

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?

Can you write down eight eights so that they add up to one thousand?

In my garden, I have many trees but only one of them is the mango tree. In these mango trees, there are some mangoes(as expected).

But after a strong wind, there are neither mangoes on the tree nor on the ground. Explain?

What has hands, but can’t clap?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

I am beautiful, up in the sky. I am magical, yet I cannot fly. To people I bring luck, and to some people, riches. The boy at my end does whatever he wishes. What am I?

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

What jumps when it walks and sits when it stands?

What time is it when an elephant sits on a fence?