Liuka problem, also called Liuka interesting problem, is an interesting topic put forward by French mathematician Liuka at an international mathematical conference in the19th century.
The topic is: A shipping company has a ship from Harvard to new york at noon every day, and a ship from new york to Harvard at the same time every day. The time the ship spent on the road came and went for seven days and seven nights, all sailing on the same route at a constant speed. How many ships of the same company will the ship leaving Harvard at noon meet on its voyage to new york?
Solutions to the Liuka problem:
The "card retention problem" is also a kind of encounter problem. If the speed of each ship is X nautical miles/day and night, when a ship happens to meet an oncoming ship, it is just one day and night away from the next ship to meet, which is X nautical miles. Therefore, the time to meet the next ship should be x÷(x+x)=0.5 (day and night), which means that a ship can meet two oncoming ships in one day and night. Then, 1 ship * * * can meet the 7×2= 14 (ship) coming from the opposite side within 7 days and nights, plus 1 ship *** 15 at the time of departure.
Pupils: every 1 minute can be changed to 1 student, and the whole journey lasts for 7 minutes.
Middle school students: