In 2012, a nation's population was 10 million. Its nominal GDP was $40 billion, and its price

Question:

In 2012, a nation's population was 10 million. Its nominal GDP was $40 billion, and its price index was 100. In 2013, its population had increased to 12 million, its nominal GDP had risen to $57.6 billion, and its price index had increased to 120. What was this nation's economic growth rate during the year?