What has many keys but can’t open a single lock?

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. 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

When can we add 2 to 11 and get 1 as the correct answer?

Which of the below owl is odd one out?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

If EELS + MARK + BEST + WARY = EASY

What does HELP + BARK + WARD + LEAD equal?

I shave every day, but my beard stays the same. What am I?

It is an eleven letter word.
The first, second, third and fourth letters form a banquet's name.
The fifth, sixth and seventh letters form a car's name.
The eighth, ninth, tenth and eleventh letters form a mode of transport.

Can you identify what word it is?

If,

6 / 7 = 2
3 / 9 = 7
8 / 2 = 6

Then

4 / 5 = ?