Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

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)

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

How Come ??

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

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 ?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

What goes through cities and fields, but never moves?

The answer I give is yes, but what I mean is no. What was the question?