Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

A blonde put eyeliner on her head. Why?

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

How can one talk without saying a single word?

A man is found dead with a knife in his back When the investigation is done. A chair lays beside him and the forensic team finds moisture around the body.

If he committed suicide, how did he do it?

Prove that twice of ten is the same as twice of eleven.

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211