Hundred rational tigers and a single sheep
Question
An island has tigers and sheep. Tigers are perfectly rational: staying alive matters most, and eating a sheep beats eating grass. At any moment at most one tiger may eat one sheep, and a tiger that eats a sheep turns into a sheep itself. How many sheep remain on the island in the end?
Short answer
. Work up from small cases: one tiger eats freely; with two, whichever eats becomes a sheep and is eaten, so none eats. With three, eating leaves a safe two-tiger state, so the sheep is eaten. The pattern alternates, and with an even number such as no tiger eats, leaving the one sheep.
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Open the worked solutionLessons behind this question
- Conditional Probability, Total Probability, and Bayes' Rule
- Worked Examples — Probability Trees, Monty Hall, and Bayesian Updating
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