1. According to the Board of Governors of the Federal Reserve System, October 10, 2017, https://www.federalreserve.gov/faqs/how-long-is-the-life-span-of-us-paper-money.htm, the average life of a one-dollar Federal Reserve note is 5.8 years. Show that at most 39%

of one-dollar bills last for at least 15 years.