Can you make four (4) nines (9) equal 100?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

Make a sentence consisting of three words that have the whole alphabet.

How many sides does a circle have?

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?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

What is always in front of you but can’t be seen?

No matter how little or how much you use me, you change me every month. What am I?