13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

John was piloting a plane behind a car but was never able to overtake it. Why?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

I have Rs.50 and I spend it in the way as below.

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3.

(You can use one number only once)

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?