CREATE TABLE table_25057 ("South American Rank" FLOAT, "World Rank" FLOAT, "Nation" TEXT, "2011  ( IMF ) " TEXT, "2008  ( CIA Factbook ) " TEXT)

Name the least world rank for south american rank 3
SELECT MIN("World Rank") FROM table_25057 WHERE "South American Rank" = '3'
SELECT MIN("World Rank") FROM "table_25057" WHERE "South American Rank" = '3'