This Infamous Birthday Math Problem Will Drive You Mad

Think you can solve it?

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Here at PopMech, we love mind-bending math and logic puzzles, which is why we regularly recruit the sharpest minds in the world to concoct riddles that will test your critical thinking, mathematics, and logic skills. The following riddle is one particularly punishing problem—so go grab a pencil and a piece of scratch paper and prepare to rip your hair out (in the best way). No cheating!

➡ The problem:

Hal and Carol accept an invitation to a house party. Hal sees that there will be 30 people attending the party and says to Carol, “I bet you $100 that at least two people will have the same birthday there!”

Should Carol take that bet? (Assume that birthdays are distributed equally over a 365-day year.)

🤫 Hint: What is the chance that no one will share a birthday in a party of a given size?

➡ The solution:

Ready for the solution? Click here to see if you’re right—and to get an insanely in-depth breakdown of how to solve this problem, plus the complete answers to almost 100 other challenging riddles.

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