Among a group of people, 10% are from NYC and 90% are not. All people from NYC are under 18 years old, and 70% of those not from NYC are also under 18 years old. One person is chosen at random, and he or she is under 18. What is the probability that the person chosen is from NYC? Round your answer to two decimal places.
i have no idea how to even begin this problem.. please help? :/