We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

You can see it everyday, But cannot touch it at will. What is it?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

One day, I thought of ways that can be used for creating a palindrome. So I decided that I will turn into a larger number by adding the reversed digits to the original number and keep doing it till I finally obtained a palindrome.

I am not sure if this process will always result in a palindrome eventually but I was able to produce a four-digit palindrome. Can you guess my starting number?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

When it's bad luck to meet a black cat?

I have two sand hourglasses:
1. A 7 minute one and
2. An 11-minute one.

Using just these 2 sand hourglasses, how can I measure time as 15 minutes?

Remove two matchsticks to make the below equation correct.

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

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?