Aarav goes to school by bus and then by train. The tree shows the chance that each is on time (O) or late (L). The chance for the train depends on how the bus ran. What is the probability that exactly one of the two journeys is late?

Fig. 1: A tree diagram with two stages. The bus is on time with probability 0.6 or late with 0.4. After an on-time bus, the train is on time with 0.65 or late with 0.35. After a late bus, the train is on time with 0.55 or late with 0.45. The four ends are labelled train on time or train late under each bus.