why number 8549176320 is one of a kind?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

I’m tall when I’m young, and I’m short when I’m old. What am I?

Why is the Hole below a Lock?

A man walked into a pub and went straight towards the Barman. He asked for a dirty martini from the Barman. The Barman thought something and then pulled out a pistol from his drawer and aimed it directly at the man. Why did he do that?

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

Replace the question mark with the number below given a simple math problem.