CREATE TABLE table_21424 ("Fin. Pos" FLOAT, "Car No." FLOAT, "Driver" TEXT, "Team" TEXT, "Laps" FLOAT, "Time/Retired" TEXT, "Grid" FLOAT, "Laps Led" FLOAT, "Points" TEXT)

Car number 15 earned what time?
SELECT "Time/Retired" FROM table_21424 WHERE "Car No." = '15'
SELECT "Time/Retired" FROM "table_21424" WHERE "Car No." = '15'