5 pirates have looted 100 coins from a tropical island. They must vote on how to divide these coins amongst each other. The voting process is as follows:

• The oldest pirate proposes a split (ex: 20, 20, 20, 20, 20)
• If the oldest pirate's plan gets at least 50% approval (he can vote for himself), the plan is passed. Otherwise he is executed and the process repeats itself with the next oldest pirate.

The process will continue until a plan is approved. How many gold coins will the oldest pirate get?

Assume the following:

• All pirates are perfectly rational and place the highest priority on staying alive

• After staying alive, all pirates seek to maximize earnings