You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?
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?
How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?
At a party, there are five people and a whole round cake lying at the centre of the table. Only four people will make a cut and take their piece and the last one will get the remaining piece on the table. How can they make sure that everyone gets a 1/5th of the piece?