A tine test is a common method used to determine whether a person has been exposed to tuberculosis. Approximately 5% of people in the United States have been exposed to tuberculosis. Using the tine test, 95% of all people who have been exposed test positive, and 98% of those not exposed test negative. Suppose a person is randomly selected and given the tine test.

(b) What is the probability that the person tests positive?

Solution: P(P)=P(E and P)+P(E' and P)=0.05(0.95)+0.95*(0.02)=0.0475+0.019=0.0665

my question is how did they get 0.02