#Math behind solving a lights out puzzle movie#

#Math behind solving a lights out puzzle movie#

Riddle #11: Can You Get These 3 Movie Stars Across the River? Difficulty: Moderate How much higher will pedestrians in the middle of the country have to reach in summer to grab the handrail? That is, in the figure below, what is h? (For the purposes of this question, ignore the curvature of the Earth and assume the trail is a straight line.) Let’s suppose when the handrail expands, it buckles upward at its weakest point, which is in the center.

“Ha!” you say, “One inch in a 4,000 mile handrail? That’s nothing!” But … are you right? But just after the opening ceremony, your assistant reminds you that the metal you used for the handrail expands slightly in summer, so that its length will increase by one inch in total. Jeffrey Ungar.įinally, the Great American Rail-Trail across the whole country is complete! Go ahead, pat yourself on the back-you’ve just installed the longest handrail in the history of the world, with 4,000 miles from beginning to end. This problem was suggested by the physicist P. Riddle #9: Can You Solve the Great American Rail-Trail Riddle? Difficulty: Moderate The trains always arrive at their scheduled times. Jesse promises he’s indeed heading to the station at a random time each day.

Both of his grandmothers are okay with this plan, since they know both the northbound and southbound trains run every 20 minutes.īut after a few months of doing this, Grandma Cara complains that she sees him only one out of five Sundays. If it happens to be the train traveling north, he’ll visit his Grandma Erica uptown, and if it happens to be the train traveling south, he’ll visit his Grandma Cara downtown. As a compromise, he tells them that every Sunday, he’ll head to the subway station nearest to his apartment at a random time of the day and will hop on the next train that arrives. Jesse’s two grandmothers want to see him every weekend, but they live on opposite sides of town. Can You Solve This Tricky Math Riddle? Difficulty: Moderate Ready for the solution? Click here to see if you’re right. You might want to try solving for the case of 10 unlabeled circuit breakers first. The solution does not involve either switching on or off the light switches in your house or feeling how hot the lightbulbs are. What is the minimum number of trips you need to make to the basement to map every circuit breaker to every light? Hint You can then roam the hallways of your house to discover which lights are on and which are off. On every trip to your basement, you can switch any number of circuit breakers on or off. To start with, you switch all 100 lights in the house to “on,” and then you head down to your basement to begin the onerous mapping process. (Suppose each circuit breaker maps to only one light.) To your chagrin, you discover none of the 100 circuit breakers is labeled, and you face the daunting prospect of matching each circuit breaker to its respective light. The circuit breaker box in your new house is in an inconvenient corner of your basement. Riddle #5: Our Circuit Breaker Riddle Is Pure Evil. The King’s Orders / How Many Eggs? / The Gold Chain / Pickleball / Circuit Breaker / Two Trains, Two Grandmas / Ant Math / Peppermint Patty / Great American Rail Trail / A Cruel SAT Problem / Movie Stars Cross a River / Tribute to a Math Genius / One Belt, One Earth / Elbow Tapping / Whiskey Problem / Doodle Problem / Stumping Scientists / What ’ s On Her Forehead? / Keanu for President / Who Opened the Lockers?

Got it wrong? No worries, you have 19 other riddles to test out. When you think you’ve got the right answer, click the link at the bottom of each riddle to find the solution. So go grab a pencil and a piece of scratch paper and prepare to rip your hair out (and we really do mean that in the best way possible). Let’s work through the toughies together. With difficulties ranging from easy, to moderate, to hard, there’s something here for everyone. Who says mind-bending logic puzzles are just for kids? We’ve come up with 20 brand-new riddles for adults to test your critical thinking, mathematics, and logic skills.