The SAT Question Everyone Got Wrong

How an SAT question became a mathematical paradox. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription.

I invented Snatoms, a molecule modeling kit where the atoms snap together magnetically. Try it at https://ve42.co/SnatomsV

Huge thanks to Dr. Doug Jungreis for taking the time to speak with us about this SAT question.

Thanks to Stellarium, a wonderful free astronomy simulator – https://ve42.co/Stellarium

Thanks to Newspapers.com, a database of historical newspapers – https://ve42.co/Newspapers

References:

Summary of this problem by MindYourDecisions – https://www.youtube.com/watch?v=kN3AOMrnEUs

More cool math about this problem by Kyle Hill – https://www.youtube.com/watch?v=_zCDbB9wvrc

Murtagh, J. (2023). The SAT Problem That Everybody Got Wrong. Scientific American – https://ve42.co/SATSciAm

United Press International (1982). Error Found in S.A.T. Question. New York Times – https://ve42.co/SAT-NYT

Yang (2020). What's the hardest SAT math problem that you've seen? Quora – https://ve42.co/SATQuora

Coin rotation paradox via Wikipedia – https://ve42.co/CoinParadox

Simmons, B. (2015). Circle revolutions rolling around another circle. MathStackExchange. – https://ve42.co/CircleRoll

Sidereal time via Wikipedia – https://ve42.co/SiderealWiki

Solar Time vs. Sidereal Time via Las Cumbres Observatory – https://ve42.co/SiderealLCO

Images & Video:

Zotti, G., et al. (2021). The Simulated Sky: Stellarium for Cultural Astronomy Research - https://ve42.co/Stellarium

Newspapers from 1980s - 1990s via Newspapers.com – https://ve42.co/Newspapers

SAT Practice Test via the College Board – https://ve42.co/PracticeSAT

Revolution Definition via NASA – https://ve42.co/RevolutionNASA

Revolution Definition via Merriam-Webster – https://ve42.co/RevolutionWebster

Earth motion animation via NASA – https://ve42.co/OrbitNASA

Satellite animation via NASA – https://ve42.co/SatNASA

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Directed by Emily Zhang

Written by Emily Zhang and Gregor Čavlović

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Filmed by Derek Muller

Produced by Emily Zhang, Gregor Čavlović, and Derek Muller

Thumbnail by Ren Hurley

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