"Since it's your birthday today," Ambrose said to his wife in a fit of generosity, "let's visit the secondhand bookshop and buy some books."
"My wife and I will join you," said his friend Benedict. "It's not her birthday, but what the heck, we can always use a few more books. What do you think, ladies?"
"Good idea," said Raquel.
"I agree," said Saffron.
They had a great time choosing books—so much so that each couple, husband and wife, spent a total of £221.
"That's strange—all my books cost the same," said Raquel. "In fact, the price of each book in pounds is exactly the same as the number of books that I've bought."
"That's funny," said Ambrose. "The same goes for me."
"Me too," chimed Benedict and Saffron in unison.
"I've got four more books than Ambrose," said Raquel.
Who is Saffron's husband?
Prospect invites you to solve the puzzle and send us the solution. Correct answers will be entered into a draw. The winner will receive a copy of Digital Dice: Computational Solutions to Practical Probability Problems by Paul J Nahin (Princeton University Press, £16.95). Nahin challenges readers to solve 21 problems, from determining the odds of coin-flipping games to figuring out the behaviour of lifts.
Send answers toinfo@prospect-magazine.co.ukby 15th May. The winner will be announced in our June issue.
