CREATE TABLE table_1307842_6 (gdp__billion_us$_ VARCHAR, gdp_per_capita__us$_ VARCHAR)

What was the gdp of the country with a gdp per capita of $18048?
SELECT gdp__billion_us$_ FROM table_1307842_6 WHERE gdp_per_capita__us$_ = 18048
SELECT "gdp__billion_us$_" FROM "table_1307842_6" WHERE "gdp_per_capita__us$_" = 18048