The Pirate Gold Problem

The problem
5 pirates · 100 gold · senior proposes split12345≥½ votes (with tie-break) ⇒ proposal passeselse senior is thrown overboard

Five pirates, ranked 1 through 5 (1 is most senior), have looted 100 gold coins. Rules:

  • The most senior pirate proposes a distribution.
  • All pirates (including the proposer) vote yes or no.
  • If at least half agree (the proposer breaks ties), the proposal passes.
  • Otherwise, the proposer is thrown overboard, and the next most senior repeats.

Every pirate is perfectly rational and greedy. Each prefers more gold, prefers staying alive, and — all else equal — enjoys throwing crewmates overboard.

What does pirate 1 propose?