If you were drifting off the coast of South America in the Atlantic Ocean, on which coast would you eventually wash up

On the coast of southwest Africa.

Explanation:

The Atlantic Ocen is the Ocen that divides the continent of Africa, and the continent of Europe form the continent of America (South, Central, and North America). If we drift off from the coast of South America, the continent that is parallel to this one in Africa, and if we look in a map, we can see that is in the southwest coast because the southeast coast of Africa has the Indian Ocean that is between Africa and Oceania.

If we look at the shape of Africa and South America, we can see that they fit one in another. The reason for this is that in the Old World, these continents were together, but then they started to drift apart, and the Atlantic Ocean came between these two continents.