What always comes into a house through the keyhole?

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

What Deficiency does the below rebus represent?

VIT_MIN

Find the combined weight of the Cat, Dog and Rabbit in the given picture.

In a kingdom, King George did not allow any citizen to visit the world outside. Also, only a person with proper paperwork was allowed to enter or he was sent back. A wooden bridge was what connected the kingdom to the world. The king had appointed a sharpshooter who would check the every five minutes on the bridge to check. After checking, he would go back to his hut and return exactly after five minutes again. The bridge took 9 minutes to cross.

A merchant was able to escape the kingdom without harming the shooter. How?

A boy collects white seashells from the sea and brings them home every night. When he has enough of them, he decides to sell them to a trader.

The trader is ready to buy the shells and he asks the boy about the quantity. At this, the boy starts calculating. He has a giant box that contains 3 mini boxes. Two of them have another mini box inside. If the giant box can hold 50 shells, how many brown shells can he sell to the trader?