18 puzzles from Alcuin of York, each explained in a minute and credited to the original work. Free on Savvy.
You must ferry a wolf, a goat and a cabbage across a river. The boat holds only you and one passenger. Left alone together, the wolf eats the goat, and the goat eats the cabbage. H…
— Alcuin of York, Propositiones ad Acuendos Juvenes ('Problems to Sharpen the Young')
A dying man leaves his three sons 30 glass flasks: 10 full of oil, 10 half-full, and 10 empty. Divide both the oil and the flasks so each son receives exactly the same amount of oi…
— Alcuin of York (attrib.), Propositiones ad Acuendos Juvenes
A ladder has 100 steps. One dove perches on the first step, two doves on the second, three on the third, one more bird on each successive step all the way up, until the hundredth s…
— Alcuin of York (attributed), Propositiones ad Acuendos Juvenes (Problems to Sharpen the Young)
A dying man leaves 960 shillings and a pregnant wife. His will says: if she bears a son, the son gets 9/12 of the estate and she gets 3/12; if a daughter, the daughter gets 7/12 an…
— Alcuin of York (attrib.), Propositiones ad Acuendos Juvenes
Three married couples need to cross a river in a boat that holds at most two people at a time. No woman may ever be in the company of a man who isn't her husband — on either bank o…
— Alcuin of York; extended by Niccolò Tartaglia, Propositiones ad Acuendos Juvenes
Two men are driving their oxen down a road. The first says to the second, 'Give me two of your oxen, and I'll have as many as you.' The second replies, 'Now give me back my two oxe…
— Alcuin of York, Propositiones ad Acuendos Juvenes
A hare stands at one end of a 150-foot field; a hound stands at the other and gives chase. Each leap of the hound covers 9 feet; each leap of the hare covers only 7 feet. Leaping a…
— Alcuin of York (attributed), Propositiones ad Acuendos Juvenes
A cask holds 7,200 pints of wine and springs three cracks at once. Through the first crack, a third plus a sixth of the wine leaks out. Through the second, exactly a third leaks ou…
— Alcuin of York (attrib.), Propositiones ad Acuendos Juvenes
A man and his wife, exactly equal in weight, want to cross a river with their two children, each of whom weighs exactly half as much as a parent. They have only one small boat, and…
— Alcuin of York, Propositiones ad Acuendos Juvenes
Alcuin of York's 9th-century puzzle collection has a man ordering 90 measures of grain moved 30 leagues to another house. He has only one camel, strong enough to carry 30 measures …
— Alcuin of York, Propositiones ad Acuendos Juvenes (Problems to Sharpen the Young)
A snail is invited by a swallow to lunch at a spot exactly one league away. There's just one problem: the snail can crawl no faster than one inch a day. Alcuin of York posed this t…
— Alcuin of York, Propositiones ad Acuendos Juvenes
Alcuin's puzzle: two merchants pool 100 coins and buy pigs at five for two coins, 250 pigs total. Selling them all together at the same rate they paid, they can't make a single coi…
— Alcuin of York, Propositiones ad Acuendos Juvenes
In Alcuin's puzzle, two walkers see a flock of storks and try to guess how many there are. They reason: if there were three times as many storks, plus half of a third of that tripl…
— Alcuin of York, Propositiones ad Acuendos Juvenes
A wealthy 8th-century head of household orders 100 bushels of corn handed out to exactly 100 people under his roof, men, women and children among them. Every man is to receive 3 bu…
— Alcuin of York, Propositiones ad Acuendos Juvenes
In one of Alcuin of York's 8th-century arithmetic riddles for students, two men marry each other's sisters. Years later, each man has a son. Alcuin's question: exactly what family …
— Alcuin of York, Propositiones ad Acuendos Juvenes
In one of Alcuin of York's medieval puzzle problems, a circular city has a circumference of 8,000 feet. Every house built inside it must measure exactly 30 feet by 20 feet. How man…
— Alcuin of York, Propositiones ad Acuendos Juvenes
A man owns 300 pigs and orders them all slaughtered over exactly three days, with an odd number killed on each of the three days. He wants the same done with a smaller herd of just…
— Alcuin of York, Propositiones ad Acuendos Juvenes
A triangular field has two equal sides of 30 perches each and a base of 18 perches. A ninth-century method for finding its area: add the two equal sides together and take half of t…
— Alcuin of York (attrib.), Propositiones ad Acuendos Juvenes