3. Let D, E, F be events such that P(D) = 0.3, P(E) = 0.4, P(F) = 0.2. Find the probability that at least one of the events D and F occurs if D and F are independent: D and F are mutually exclusive. Find the probability that all of the events D, E, F occur if D, E, F are independent: D, E, F are mutually exclusive.