Puzzles
Five rational pirates must vote on how to split 100 gold coins, or die trying
Five pirates, ranked by seniority, must split 100 gold coins. The most senior proposes a split; all pirates including the proposer vote, and if at least half approve, it happens — otherwise the proposer is thrown overboard and the next-most-senior pirate proposes instead. Every pirate is perfectly rational, greedy, and would rather see a rival dead than gain nothing. What does the most senior pirate propose?
Reveal the answer
98 coins for himself, 1 each to the third- and fifth-most senior pirates, 0 to the rest. Working backward from a two-pirate scenario shows each pirate needs to buy just enough votes from whoever would otherwise get nothing under the next proposer's plan — a clean demonstration of backward induction in game theory.