Why do we preferably have round manhole covers and not square ones?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

You visit a home for specially-abled children on the occasion of Christmas where you meet with 50 children. You have a box of chocolates containing 50 chocolates exactly.

What if you were asked to one chocolate to each child in a manner that one chocolate still remains in the box? Is it possible?

Okay before we begin with the puzzle, do keep in mind that you have to answer it quickly.

You are participating in a car race. Seeking the perfect moment, you overtake the second person in the race. What positions are you in now?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

Can you name four days which start with the letter 'T'?

Replace the letters of words with a number so that the below equation holds true

BASE +
BALL
---------
GAMES
----------

Can you decipher the below rebus?

PBLUESAISNUERSES