You fill both ships. There's not much loss in efficiency, just separating hazardous material. Maybe you should look up how many ships full of oil it takes to power all of the gasoline powered cars. It's a lot.
One for the oil and one for the cars. That's two. Actually it's more like 10 because each car requires ~200 barrels of oil to produce the gasoline it's going to use over its lifetime.
You fill both ships. There's not much loss in efficiency, just separating hazardous material. Maybe you should look up how many ships full of oil it takes to power all of the gasoline powered cars. It's a lot.
One for the oil and one for the cars. That's two. Actually it's more like 10 because each car requires ~200 barrels of oil to produce the gasoline it's going to use over its lifetime.