Photograph: Allstar/PARAMOUNT
Family relationships have provided material for many classic puzzles since at least medieval times. They make for fun problems because they require no technical knowledge and often present entertaining or curious set-ups. Here are a selection of five of my favourites of the genre.
1) Anna’s father has four daughters. The names of the first three daughters are April, May and June. What’s the name of the fourth daughter?
2) Two men marry each other’s mothers. What is the relationship between their sons?
3) A certain man had great grandchildren, yet none of his grandchildren had any children. How come?
4) What’s the smallest possible number of people in a family group that contains a grandfather, a grandmother, two fathers, two mothers, four children, three grandchildren, one brother, two sisters, two sons, two daughters, one father-in-law, one mother-in-law and one daughter-in-law?
5) On one day my friend Olivia has her birthday. Two days later it is the birthday of her elder twin, Oliver. Please explain.
I’ll be back with the answers at 5pm.
UPDATE: Read the solutions here.
Meanwhile, NO SPOILERS. Please pose your favourite family puzzles.
I set a puzzle here every two weeks on a Monday. I’m always on the look-out for great puzzles. If you would like to suggest one, email me.
I’m the author of several books of popular maths and the Football School book series for kids that explains the world through football.
Sources for today’s puzzles: 1) widely known 2) Alcuin, Propositiones ad Acuendos Juvenes, 3) Raymond Smullyan, A Mixed Bag 4) Ian Stewart, Cabinet of Mathematical Curiosities 5) Des MacHale and Paul Sloane, Hall of Fame Lateral Thinking Puzzles.
