The centre of the third figure is empty. What digit should fit inside?

Chhote se Chintu Miyan,
Lambi si Pooch.
Jahan Jaye Chintu Miyan,
Wahan Jaye Pooch.

छोटे से चींटू मियाँ,
लंबी सी पूंछ।
जहाँ जाये चींटू मियाँ,
वहाँ जाये पूंछ।

Bolo kya?

You can hear me, but you can't touch or see me.

What am I?

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

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

What jumps when it walks and sits when it stands?

What is the coolest letter in the alphabet?

I know a nine-letter word having only one vowel.
Do you ?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

A woman lives in a Tall building thirty-six floors high and served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?