Alcuin's Basilica Paving Puzzle
A basilica measures 240 feet long and 120 feet wide. Its floor is to be paved edge to edge, with no gaps or overlaps, using identical rectangular stones that each measure 1 foot 11 inches by 1 foot. How many stones in total does it take to pave the entire basilica floor?
Reveal the answer
15,120 stones — 126 fit along the 240-foot length and 120 along the 120-foot width, and 126 × 120 = 15,120. It's one of Alcuin of York's Propositiones ad Acuendos Juvenes (c. 800 CE), a tiling problem written thirteen centuries before anyone thought to call it 'flooring.'
— Alcuin of York, Propositiones ad Acuendos Juvenes — A problem on paving a basilica, c. 800 CE