In an article about investment alternatives, Money magazine reported that drug stocks provide a potential for long-term growth, with over 50% of the adult population of the United States taking prescription drugs on a regular basis. For adults age 65 and older, 82% take prescription drugs regularly. For adults age 18 to 64, 49% take prescription drugs regularly. The age 18-64 age group accounts for 83.5% of the adult population (Statistical Abstract of the United States, 2008).
a. What is the probability that a randomly selected adult is 65 or older (to 3 decimals)?