Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Can you move 2 matchsticks to form four equal sized squares.

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

The warden meets with 23 new prisoners when they arrive. He tells them, "You may meet today and plan a strategy. But after today, you will be in isolated cells and will have no communication with one another.

"In the prison is a switch room, which contains two light switches labeled 1 and 2, each of which can be in either up or the down position. I am not telling you their present positions. The switches are not connected to anything.

"After today, from time to time whenever I feel so inclined, I will select one prisoner at random and escort him to the switch room. This prisoner will select one of the two switches and reverse its position. He must flip one switch when he visits the switch room, and may only flip one of the switches. Then he'll be led back to his cell.

"No one else will be allowed to alter the switches until I lead the next prisoner into the switch room. I'm going to choose prisoners at random. I may choose the same guy three times in a row, or I may jump around and come back. I will not touch the switches, if I wanted you dead you would already be dead.

"Given enough time, everyone will eventually visit the switch room the same number of times as everyone else. At any time, anyone may declare to me, 'We have all visited the switch room.'

"If it is true, then you will all be set free. If it is false, and somebody has not yet visited the switch room, you will all die horribly. You will be carefully monitored, and any attempt to break any of these rules will result in instant death to all of you"

What is the strategy they come up with so that they can be free?

Two friends were stuck in a cottage. They had nothing to do and thus they started playing cards. Suddenly the power went off and Friend 1 inverted the position of 15 cards in the normal deck of 52 cards and shuffled it. Now he asked Friend 2 to divide the cards into two piles (need not be equal) with equal number of cards facing up. The room was quite dark and Friend 2 could not see the cards. He thinks for a while and then divides the cards in two piles.

On checking, the count of cards facing up is same in both the piles. How could Friend 2 have done it ?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

A father's child, a mother's child, yet no one's son.

Who am I?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

Tarang football website was hacked by one of the players. Jack, the coach of Tarang has pointed out five players as the possible hacker.
Each suspected player made three statements from each suspected player and out of which two are true and one is false.

Joseph
A) I have not hacked the website.
B) I know nothing about hacking.
C) John did it.

Hazard
A) I have not hacked the website.
B) The website was attacked by one of the players.
C) I hate Shelly

Remy
A) I have not hacked the website.
B) I have never seen Oscar in my entire life.
C) I am sure John did it.

John
A) I have not hacked the website.
B) I am sure Oscar did it.
C) Joseph was lying when he said he did it.

Oscar
A) I have not hacked the website.
B) I am sure Hazard did it.
C) I used to be friend with Remy.

So who hacked the website?