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

O T T F F S S ?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

From a pack of 52 cards, I placed 4 cards on the table.

I will give you 4 clues about the cards:

Clue 1: Card on left cannot be greater than the card on the right.
Clue 2: Difference between the 1st card and 3rd card is 8.
Clue 3: There is no card of an ace.
Clue 4: There are no face cards (queen, king, jacks).
Clue 5: Difference between the 2nd card and 4th card is 7.

Identify four cards?

In an office's desk, you find a unique method that shows the current day of the month. Two numbered cubes are used to depict the current date.

Can you find out the numbers on both the cubes so that each date can be mentioned using them?

Please note that you have to use both the cubes to display any date. Thus the 1st day must be represented by 01 and so on.

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

What word is represented by this rebus?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

Count the number of squares in the picture below.