What Adam and Eve do not have but the rest of the people have?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

Identify the movie name through below Rebus containing Pi Mouse and coconut tree..

What has to be broken before you can use it?

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

He loves to dance, twist and prance, he shakes his tail, and as a way he sails, wingless he flies into the sky. What is he?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?