Answer: Sam and Morgan met up at 18:00. Sam left Exeter at 10:00, and was on the road for 7 hours. I know this because 175 / 25 = 7. 10:00 + 7:00 = 17:00 meaning Sam got there at 17:00. Morgan on the other hand left at 13:00 and had an average speed of 35 mph. 175/35=5. 13:00 + 5:00 = 18:00. By 18:00 both Sam and Morgan had arrived in London thus 18:00 us your answer.
