riddle

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Your research team has found a prehistoric virus preserved in the permafrost and isolated it for study. After a late night working, you’re just closing up the lab when a sudden earthquake hits and breaks all the sample vials. Will you be able to destroy the virus before the vents open and unleash a deadly airborne plague? Lisa Winer shows how.

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Your rich, eccentric uncle just passed away, and you and your 99 nasty relatives have been invited to the reading of his will. He wanted to leave all of his money to you, but he knew that if he did, your relatives would pester you forever. Can you solve the riddle he left for you and get the inheritance? Lisa Winer shows how.

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You’re stranded in a rainforest, and you’ve eaten a poisonous mushroom. To save your life, you need an antidote excreted by a certain species of frog. Unfortunately, only the female frog produces the antidote. The male and female look identical, but the male frog has a distinctive croak. Derek Abbott shows how to use conditional probability to make sure you lick the right frog and get out alive.

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Townspeople are demanding that a corrupt merchant’s collection of 30 rubies be confiscated to reimburse the victims of his schemes. The king announces that the fine will be determined through a game of wits between the merchant and the king’s most clever advisor – you. Can you outfox the merchant and win back the greatest amount of rubies to help his victims? Dennis Shasha shows how.

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The city has just opened its one-of-a-kind Faberge Egg Museum, with a single egg displayed on each floor of a 100-story building -- and the world’s most notorious jewel thief already has her eyes on the prize. Can you help the thief formulate a plan that will drop the most expensive egg she can get safely into her waiting truck? Yossi Elran shows how.

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A challenging logic puzzle involving strategy and probability.

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A classic logic puzzle to test your problem-solving.

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In a dystopian world, your resistance group is humanity’s last hope. Unfortunately, you’ve all been captured by the tyrannical rulers and brought to the ancient coliseum for their deadly entertainment. Will you be able to solve the passcode riddle and get everyone out safely? Ganesh Pai shows how.

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You and your team have crash-landed on an ancient planet. Can you appease the three alien overlords who rule it and get your team safely home? Created by logician Raymond Smullyan, and popularized by his colleague George Boolos, this riddle has been called the hardest logic puzzle ever. Alex Gendler shows how to solve it.

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Your expedition finally stands at the heart of the ancient temple. But as you study the inscriptions in the darkness, two wisps of green smoke burst forth. The walls begin to shake. The giant sandglass begins flowing with less than an hour before it empties, and a rumbling tells you that you don’t want to be around when that happens. Can you use math to escape the temple? Dennis E. Shasha shows how.

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Once a year, thousands of logicians descend into the desert for Learning Man. At the center of that gathering is the world’s most exclusive club, where under the full moon the annual logician’s rave takes place. The entry is guarded by the Demon of Reason, and the only way in is to solve one of his dastardly challenges. Can you get into the rave? Edwin Meyer shows how.

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The underworld is overcrowded, and Zeus has ordered Hades to let some spirits out. Hades arranges all the souls of the dead in a line before Cerberus. When one of his three heads bites down on the soul in front of it, they’ll get returned to the land of the living. Anyone to the left must stay in Hades forever. Can you pick the right spot and escape the underworld? Dan Finkel shows how.

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As Numberland’s best detective, you thought you’d seen it all. But the desiccated corpses of prominent natural numbers have been showing up all over the city. A lockdown is ordered from sundown to sunrise, and it’s still not enough to stop what can only be described as a vampiric feeding frenzy. Can you figure out why the citizens of Numberland are being attacked? Henri Picciotto shows how.

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Your timing made you and your partner infamous bank robbers. Now, you need to use that timing to break out of jail. Your partner is about to flash you a signal, and exactly 45 seconds later the electric fence circuit will short out. Then you notice that your watch is broken, and all you have are two 1-minute fuses in your pocket. Can you time your escape and get free? Dan Finkel shows how.

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You’ve stealthily descended into the darkness of a vampire cave, setting a sequence of mirrors as you go. When the sun reaches the right angle in the sky, a beam of light will ricochet along the mirrors, strike a diffuser, and illuminate the great chamber where the vampires sleep. Can you place the diffuser correctly and flood the lair with sunlight? Dan Finkel shows how.

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As a world-renowned treasure hunter, you have been searching for the legendary dungeon containing the stash of ancient Stygian coins. The wizard who owns the castle has even allowed you to have them, on one condition…you must solve his seemingly impossible puzzle.

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The world turns on symmetry -- from the spin of subatomic particles to the dizzying beauty of an arabesque. But there's more to it than meets the eye. Here, Oxford mathematician Marcus du Sautoy offers a glimpse of the invisible numbers that marry all symmetrical objects. Oxford's newest science ambassador Marcus du Sautoy is also author of The Times' Sexy Maths column. He'll take you footballing with prime numbers, whopping symmetry groups, higher dimensions and other brow-furrowers.

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After years of experiments, you’ve finally created the pets of the future – nano-rabbits! They’re tiny, they’re fuzzy ... and they multiply faster than the eye can see. But a rival lab has sabotaged you, threatening the survival of your new friends. Can you figure out how to avert this hare-raising catastrophe? Alex Gendler shows how.

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You’ve promised to get your son the cutest creature in creation: the cuddly. It’s part of the Wuddly species, cousin to the terrifying duddly and the hideous fuddly. To make one, 100 eggs are placed in an incubator to undergo egg fusion, and the resulting combination will produce either a cuddly, a duddly or a fuddly. Can you make the right combination to get a cuddly? Dan Finkel shows how.