The Southern Ocean, also known as the Antarctic Ocean or the Austral Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. As such, it is regarded as the second-smallest of the five principal oceanic divisions: smaller than the Pacific, Atlantic, and Indian Oceans but larger than the Arctic Ocean. This oceanic zone is where cold, northward flowing waters from the Antarctic mix with warmer subantarctic waters.
Let x and y be the numbers; We have x + 2y = 9 and 2x + y = 21; Then, x = 9 - 2y; Finally, 2(9-2y) + y = 21 ; 18 - 4y + y = 21; 18 - 3y = 21; -3y = 3; y = - 1; x = 9 - 2× (-1); x = 9 + 2 ; x = 11;
