When 99 is considered higher than 100?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

They are three errirs in this question. Can you find them?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

Which alphabet letter is a question?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

What question can you never answer yes to?