In an article about investment alternatives, Money magazine reported that over 50% of the adult population in the USA takes prescription drugs on a regular basis. For adults age 65 or older, 82% take prescription drugs regularly. For adults age 18 to 64, 49% take prescription drugs regularly. The group 18-64 accounts for 83.5% of the adult population.
What is the probability that a randomly selected adult is 65 or older and given an adult takes prescription drugs regularly, what is the probability that the adult is 65 or older?