What is the longest word in the dictionary?

Solve the following series:
AZ, GT, MN, __, YB

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

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

Two batsman each on 94 runs. Seven runs needed to win in last 3 balls. Both make 100*. How?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Count the Triangle in the figure given below:

The below mentioned letters have been placed in a order using a logic.

DEAD, BALL, FEAR, SHOP

Can you find the logic?

12345 a famous South Indian actor
567 is a path in jumbled form
8 & 10 are same letters
9 is one among the first six alphabets.
WHO AM I?