What is the coolest letter in the alphabet?

Before Mount Everest was discovered, what was the highest mountain in the world?

Detective Rockford was jogging near the beach at 4:30 am.
He hears a sound near the shack "No Michael, Please Do not shoot me".
Next instance he heard the sound of gunfire. Rockford rushes to the shack where he finds women lying dead and a gun in close proximity of three "Doctore Lawyer and a Teacher".

Rockford immediately knew that the Lawyer has committed the crime. How?

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

I have branches, but no fruit, trunk or leaves. What am I?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

What is the next number in the series?

15 29 56 108 208 ?

If,

Akriti = 631
Levis = 521
Sroti = 521
Aneel = 533
Then,
Sunil =?

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

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?