Clare and Lin are running in a race. The equation y = 9.5x represents one person's progress. If one person has a head start, how long until the other catches up. The equation y = 9.5x represents Lin's progress where y represents he distance, in feet, from the starting line, and x represents the time. in seconds, that she has been running. Clare has the head start. She is 18ft in front of the starting line when Lin begins running, Clare runs at a constant 8ft per second.