Living in the Environment 18th Edition by Tyler Miller,Scott Spoolman

Exercise 7

Rare-earth metals are widely used in a variety of important products ( Core Case Study ). In 2010, China produced about 97% of the world's rare earths and the United States produced none. According to the U.S. Geological Survey, China has 50% of the world's reserves of rare-earth metals and the United States has 13%.
Global demand for rare earths is projected to rise to at least 185,000 metric tons by 2015. If China produced all of the world's rare-earth metals how long would its reserves last