Example A student goes to the library. The probability that she checks out (a) ca as a work of fiction is 0.40, (b) a work of non-fiction is 0.30, , and (c) both fiction and non-fiction is 0.20. What is the probability that the student checks out a work of fiction, non-fiction, or both? Solution: Let F = the event that the student checks out fiction; and let N = the event that the student checks out non-fiction. Then, based on the rule of addition: P(FUN) = P(F) + P(N) P(F n N) P(FUN) = 0.40 + 0.30 -0.20 = 0.50 Test Your Understanding of This Lesson Problem 1 An urn contains 6 red marbles and 4 black marbles. Two marbles are drawn with replacement from the urn. What is the probability that both of the marbles are black? (A) 0.16 (B) 0.32 0.36 0.40 0.60 MOO