How can you write nineteen in a manner that if we take out one, it becomes twenty?

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?

Which number comes next in the number series?

2, 9, 30, 93, ?

What is wrong in the below Picture?

The answer I give is yes, but what I mean is no. What was the question?

Find the Goldfish below the given Image.

Why is the Hole below a Lock?

What building has the most stories?

What demands an answer, but asks no questions

I always drive my customer away.

Who am I?