I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

Prove that twice of ten is the same as twice of eleven.

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?

A Detective reviewed the information they had on the case so far.

A lady named 'Caterina' was found shot and they already had a list of suspects - Ankit, Tarun, Harish, Manoj and Manish.
The killer is a fan of challenges him by leaving notes ad various places.
* The first was found in a toilet room.
* The second was found in an art room.
* The third was in a restroom.
* the fourth in an underwater room.
* The fifth at the no-smoking room.

All of the notes read the same thing, 'The clues are where you find the notes.' Yet, nothing was found at any place the notes were.
Detective the genius, immediately solved the case.
Who was the killer?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

Dr Doom invited a group of puzzle fanatics to a party which was oriented toward having puzzle-oriented games. At night, he introduced the guests to a 'unique riddle'. A prize was offered to the one who solved it first.

The guests included six people named Tom Paul, Fox Obama, Jeremy Reener, Alex Murphy, Prim Pastor, and Ellen Page. The winner of the 'unique riddle' contest was to be announced after the dinner. So Dr. Doom stood up and started the announcement:

'Okay now everybody!'
'The winner of�'
'The Hardest Riddle Ever Event'

But before he could complete it, the light went out and his voice was not heard without the mic by anyone. But they already knew who the winner was. Can you deduce the name of the winner?

If,

A + B = C
D - C = A
E - B = C

Based on the above equations, find out the answer for:

D + F = ?

A bank customer had $100 in his account. He then made 6 withdrawals. He kept a record of these withdrawals, and the balance remaining in the account, as follows:

Withdrawals Balance left
$50 $50
$25 $25
$10 $15
$8 $7
$5 $2
$2 $0
----- -----
$100 $99

Why are the Totals not tallying?

John was drowned by he was not wet. How?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?