A record-store owner assesses customers entering the
store as high school age, college age, or older, and
finds that of all customers 30%, 50%, and 20%, respectively, fall into these categories. The owner also found
that purchases were made by 20% of high school age
customers, by 60% of college age customers, and by
80% of older customers.
a. What is the probability that a randomly
chosen customer entering the store will make a
purchase?