There is a bus full of people travelling over San Francisco and no one gets off the bus throughout the journey. But when it gets to the other side there is not a single person left. How is this possible?
They are all married.
Bạn thử chứng minh "3n = 4 với mọi n" thử xem nào?
3n = Ba n
4 = Bốn = Bố n