Puzzles
A mule and a donkey argue about who's carrying more sacks of grain
A mule complains to a donkey: 'If you gave me one of your sacks, I'd be carrying exactly twice as many as you. But if I gave you one of mine instead, we'd be carrying the same number.' How many sacks is each animal carrying?
Reveal the answer
The mule carries 7 sacks and the donkey carries 5. Check it: give the mule one of the donkey's sacks and it's 8 versus 4 (double); give the donkey one of the mule's and it's 6 versus 6 (equal). It's one of the algebraic riddles preserved in Book XIV of the 'Greek Anthology,' a collection of epigram-puzzles compiled from older Greek sources, around the 5th century CE.