answer with explanation

8- There is 99% chance that the result of a hepatitis test turns positive if the patient actually has hepatitis. The hepatitis test turna positive with a probability of 5% for a patient that does not actually have hepatitis, Assume that 70% of those who walk into the lab center have hepatitis. If we choose a person randomly and if we know that his test result is positive, what is the probability that he has hepatitis