A puzzle set 1,200 years ago — and its own author got it wrong
A wine cellar is 100 feet long and 64 feet wide. Each wine cask is 7 feet long and 4 feet wide, and a 4-foot-wide aisle runs through the cellar for access. How many casks fit inside?
Reveal the answer
Alcuin's own 9th-century answer was 210 casks. Centuries later, mathematicians re-examining the puzzle showed a simple centred aisle actually fits 212, and a cleverer off-centre aisle fits 214 — concluding that Alcuin, in the words of his modern annotators, 'did not realise the subtleties of a very nice problem' he himself had posed.