Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

I organized a small get together at my home.
In the party , i have a barrel with some whiskey in it.

Suddenly Guest 1 say 'I bet this barrel of whiskey is more than half full'.
'No, it's less than half full' Guest 2 replied.

I don't have any measuring instrument and without removing whiskey from it , how can i determine which of the guest is right ?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

When it is alive we sing, when it is dead we clap our hands. What is it?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...