Medium · Probability & Combinatorics · Numerical · ~4 min · #103
51 Coins Against 50
Real interview · Squarepoint Capital
You toss 51 fair coins and I toss 50. You win only if you get strictly more heads than I do. What is your probability of winning?
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Worked solution
Give the problem an honest attempt first, then reveal the full explanation.
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Concepts
SymmetryConditioning on the last coin
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Quant TraderQuant Researcher