Kordemsky's five apples in a basket
Five apples sit in a basket. Can you divide them among five girls so that each girl receives an apple of her own - and yet one apple is still left behind in the basket?
Reveal the answer
Give four of the girls an apple each, then give the fifth girl her apple still sitting inside the basket: she gets an apple, and one apple (hers) remains in the basket, exactly as asked. It's 'Five Apples,' problem 7 in the 'Amusing Problems' chapter that opens Boris Kordemsky's The Moscow Puzzles, first published in the Soviet Union in 1956 and, for decades, the best-selling puzzle book in Russian history; Martin Gardner introduced it to English-language readers as editor of the 1972 translation.
— Boris A. Kordemsky, The Moscow Puzzles: 359 Mathematical Recreations — Chapter 1, 'Amusing Problems,' Problem 7 ('Five Apples'); 1956 Russian original, 1972 English translation
Go deeper: get the book →