Seeker's first spot turning up empty
Question
Two players each choose one of five hiding places independently and uniformly at random (they may pick the same one). A seeker then searches one of the five places, also chosen uniformly at random. What is the probability that nobody is hiding in the place the seeker checks first?
Short answer
. Whatever spot the seeker picks, each hider independently avoids it with probability , so the spot is empty with probability .
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Open the worked solutionLessons behind this question
- Conditional Probability, Total Probability, and Bayes' Rule
- Counting and Combinatorics
- Worked Examples — Probability Trees, Monty Hall, and Bayesian Updating
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