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

تمرين 3

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%.
In 2010, the global demand for rare-earth metals was about 133,600 metric tons. If China produced all of the world's rare-earth metals, how long would their reserves last