The President of Puzzeland has purchased two second-hand gunships to protect his island nation. They are rather old, and can only carry enough fuel to travel 120 miles, which takes 24 hours. The President is planning a voyage around the island to show off the ships, but Puzzeland has a coastline that is greater than 120 miles, which is a problem!
The ships can transfer fuel between them while at sea, which does open up some opportunities, and the Lord High Admiral has found a solution.
One ship will be able to steam around the entire country, with the other supplying it with fuel. In fact, neither ship will have to wait at anchor for the other, and they will only be stationary while transferring fuel. Oh, and it takes eight hours to refuel while in port.
As it happens, if the coastline of Puzzeland was any longer the voyage would not be possible. How long is Puzzeland's coastline, and how does the refuelling scheme work?
The voyage around Puzzeland is 200 miles, and it is achieved as follows:
- Both ships steam around the island together for 40 miles,
- The support ship transfers half its remaining fuel to the main ship, and returns to port,
- The main ship continues around the island, and the support ship refuels in port,
- The support ship sets off in the other direction to meet the main ship.
- After 40 miles the support ship meets the main ship, and transfers half its remaining fuel once again.
- Both ships steam into port together.