Xavier is doing some athletics training. He runs for 5 minutes, covering one kilometres, and then he rests for 5 minutes. He continues in this way until he has run 4 kilometres. a. show this on a graph with time on the horizontal axis and distance on the vertical axis.
b. 10 minutes after xavier has started. Alicia runs after him. she runs at the same speed but witihout stopping, for 4 kilometres. show this on the graph.
c. explain how the graph shows that they are running together for part of the time.