Tarawa is an atoll and the capital of the Republic of Kiribati, in the central Pacific Ocean. It comprises North Tarawa, which has much in common with other, more remote islands of the Gilberts group; and South Tarawa, which is home to 50,182 as of 2010 – half of the country's total population. The atoll is best known by outsiders as the site of the Battle of Tarawa during World War II.
North Tarawa is home to half of the country's total population as of 2010. 
Contextually, we are told that the country is made up of North Tarawa and South Tarawa, so, if half of the country is populating South Tarawa, it is logically a correct statement to conclude that the other half lives in the only other portion that comprises the country's division.  AI cannot think logically beyond the scope of info provided.