What country can make you shiver?

I have some blue and red sock in my drawer. I have a total of 4 socks. I pick 2 socks and the chance that I get a pair of red socks is 1/2.

What is the chance of picking a pair of blue socks?

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

Rahul decided to meet Simran so he boards a local train from Bombay station. Just after the station, there is a 1km long tunnel. The train starts and is now accelerating. Rahul is a claustrophobic guy, so what is the best position for him to sit?

A father's child, a mother's child, yet no one's son.

Who am I?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

Who has married many women but was never married?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

I cannot talk, but I always reply when spoken to. What am I?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?