A large container is kept in open under the rain. Every passing hour, the water collected inside the container becomes double what it was.

In ten hours, the container is filled completely. Can you calculate how long would it have taken to be filled in half?

How many triangles can you find in this given picture?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

The day after tomorrow will be three days before Tuesday. Can you find out what is today?

Can you count the number of quadrilaterals in the picture below?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

There are hundred red gems and hundred blue gems. The blue gems are priceless while the red gems equal wastage. You have two sacks one labeled Heads and the other Tails. You have to distribute the gems as you want in the two sacks. Then a coin will be flipped and you will be asked to pick up a gem randomly from the corresponding sacks.

How will you distribute the gems between the sacks so that the odds of picking a Blue gem are maximum?

What makes this number unique: 8,549,176,320?