Puzzle
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Probability
Ride-sharing: What the Wait Time Tells You
An 8-minute wait sounds like evidence of surge pricing. The math says otherwise: it barely shifts your estimate from the prior. Using exponential wait-time distributions, Bayes' theorem, and simple cost-benefit analysis, this puzzle explores why observed data can be surprisingly uninformative.
April 29, 2026
Probability
How Big Is Half a Lottery?
A $1 billion jackpot. Seven numbers, drawn with replacement from 1–19. You want a 50% chance of winning. How many $1 tickets must you buy — and will it ever be worth it?
April 15, 2026
Probability
Elevator Probability
You enter a building with 12 floors and press your floor at random. What is the expected number of stops if 3 other passengers do the same?
February 14, 2026