Need working for these questions as I am not sure if I have done it accurately

Problem 1. Joe is a randomly chosen member of a large population in which 3% are heroin users. Joe went for a test that correctly identifies users 95% of the time and correctly identifies nonusers 90% of the time. (a) Given that Joe is not a heroin user, find the probability that he tests positive. (b) Given that Joe tested positive, find the probability that he is a heroin user. (c) Given that Joe tested negative, find the probability that he is not a heroin user. Problem 2. Suppose that one person in 10,000 people has a rare genetic disease. There is an excellent test for the disease: 99.9% of people with the disease test positive and only 0.02% who do not have the disease test positive. a) What is the probability that someone who tests positive has the genetic disease? b) What is the probability that someone who tests negative does not have the disease