What always comes into a house through the keyhole?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

'S' refers to the number of seconds in a day and 'H' refers to the number of hours in ten years. Which quantity out of these two is greater?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

There is something which is always coming but never arrives?

As you can see in the picture, you have a hole with dimensions 9 ft x 2 ft Also available is a wooden board with dimensions 6 ft x 3 ft Now you have to cover the hole with this board and you are allowed to cut the board into two pieces. Please see that the hole is completely covered and the boards should not overlap or extend beyond the edge. How will you cut the board?

A farmer and his neighbour once went to Emperor Akbar"s court with a complaint. "Your Majesty, I bought a well from him," said the farmer pointing to his neighbour, "and now he wants me to pay for the water."
"That"s right, your Majesty," said the neighbour. "I sold him the well but not the water!"?
The Emperor asked Birbal to settle the dispute. How did Birbal solve the dispute?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

What does below chemistry rebus means?

How can one talk without saying a single word?