P(A or B) = P(A) + P(B) - P(A and B), which means that the probability that A or B occurs
is equal to the probability that A occurs plus the probability that B occurs minus the probability that both A and B occur.
So, you know P(A), P(B) and P(A or B) and you can solve for P A and B) =>
P(A and B) = P(A) + P(B) - P(A or B)
P(A and B) = 0.5 + 0.3 - 0.6 = 0.8 - 0.6 = 0.2
Answer: P(A and B) = 0.2
