How can a man go eight days without sleep?

John and Jacob are playing bets. John gives $10 to Jacob and Jacob deals four cards out of a normal 52-card deck which are chosen by him completely randomly. Jacob keeps them facing down takes the first card and shows it to John. John has a choice of either keeping it or looking at the second card. When the second card is shown to him, he again has the choice of keeping or looking at the third which is followed by the third card as well; only if he does not want the third card, he will have to keep the fourth card.

If the card that John is choosing is n, Jacob will give it to him. Then the cards will be shuffled and the game will be played repeatedly. Now you might think that it all depends on chance, but John has come up with a strategy that will help him turn the favor in his odds.

Can you deduce the strategy of John?

What do you answer even though it never asks you questions?

If I put in one bird per cage, I have one bird too many. If I put in two bird per cage, I have one cage too many. How many cages and birds do I have?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

What kind of tree can you carry in your hand?

A large container is kept in open under the rain. Every passing hour, the water collected inside the container becomes double what it was.

In ten hours, the container is filled completely. Can you calculate how long would it have taken to be filled in half?

Daniel walks into a movie theatre. While in the movie, he suddenly smiles delightfully. About a couple of minutes later, he seems shocked. He walks out of the theatre, goes to a bridge and jumps over the edge killing himself.

Why did he do it?

Note: Think Lateral

I cannot talk, but I always reply when spoken to. What am I?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?