How many sides does a circle have?

Find the missing number in the image below.

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

Why is the longest human nose just 11 inches?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

John is found dead in a bare field. Nobody killed John,
John did not commit suicide.

Inspector Jacob found a bag just a few meters away from John which could save his life. What was in the bag?

Two friends Smith and Andrew were talking about the bravery of their families. Smith told great stories about his courageous grandfather who fought for Britain in "World War I". Andrew told that his grandfather was so brave that in 1919 just after the war he was honoured with a bravery medal with the words "For our Courageous Soldiers In World War I" embedded into it. Smith knows that his friend is lying. How?

How could a baby fall out of a twenty-story building onto the ground and live?