A store recently released a new line of alarm clocks that emits a smell to wake you up in the morning. The head of sales tracked buyers' ages and which smells they preferred.
The probability that a buyer is an adult is 0.9, the probability that a buyer purchased a clock
scented like cotton candy is 0.9, and the probability that a buyer is an adult and purchased a
clock scented like cotton candy is 0.8.
What is the probability that a randomly chosen buyer is an adult or purchased a clock scented
like cotton candy?