A deaf and mute man goes to the train station. Tickets for the train are 50 cents each. The man goes to the ticket booth and hands the man inside just a dollar. The man in the booth hands him two tickets.
How did the man in the booth know to give him two tickets without even looking at him?
In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:
What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?
Oedipus solved the riddle, and the Sphinx destroyed herself.
Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?
A non-stop marathon is the shared favourite sport of three brothers.
*The oldest one is fat and short and trudges slowly on.
*The middle brother's tall and slim and keeps a steady pace.
*The youngest runs just like the wind, speeding through the race.
"He is young in years, we let him run!" the other two brothers explained, "'because though he is surely number one, he is second, in a way." Why is it?
In 2011, people playing Foldit, an online puzzle game about protein folding, resolved the structure of an enzyme that causes an Aids-like disease in monkeys. Researchers had been working on the problem for 13 years. The gamers solved it in three weeks.