What is the western border of the continent that has 3 countries who use the rand rather than their own legal tender?
South African rand:  The rand is legal tender in the Common Monetary Area between South Africa, Swaziland, Lesotho, and Namibia, although the latter three countries do have their own currencies. Namibia: Namibia ( , ), officially the Republic of Namibia (German:    ; Afrikaans: "Republiek van Namibië" ) is a country in southern Africa whose western border is the Atlantic Ocean.
Atlantic Ocean