I need help please to answer this i have exam in 2 hours?

suppose that in a certain population , one-tenth of 1% of all individuals are infected with the HIV virus that causes AIDS. Tests for the presence of the virus are imperfect. Suppose that 95% of those who are infected test positive; 2% of those who really are not infected also test positive. if a randomly chosen person tests positive, what is the probability that the person really has the HIV virus?