At a certain college, 15% of the students received an A in their required math course, 10% receieved an A in their required chemistry course, and 5% received an A in both. A student is selected at random.
a.) What is the probability that he received an A in either chemistry or math?
b.) What is the probability that he received an A in chemistry, if he had an A in math?
c.) What is the probability that he received an A in math, if he had an A in chemistry?
d.) Are the events " A in math" and "A in chemistry" independent?