Each point in the graph has two coordinates, X and Y, X is the horizontal position (minutes) and Y is the vertical (distance from home). We can see in the plot that both Pilar and Tom started at (0;9.5), however, Pilar arrives at the house (Y=0) after 7 minutes, and Tom after seemingly 9.5 minutes.
So Pilar's Speed (now P) is:

And Tom's Speed (now T) is:

Som Pilar's rate is higher than Tom's. S > T