The probability that a regularly scheduled flight departs on time is P(D) = 0.83, the probability that it arrives on time is P(A) = 0.92, and the probability that it both departs and arrives on time is P(A ∩ D) = 0.78. Find the probability that a flight

(a) Arrives on time given that it departed on time;

(b) Did not depart on time given that it fails to arrive on time.