Answers:
The graph is attached below. With this information we have to answer the questions:
1) Who is at the trail start at 9:00 a.m.?
Andy
According to the graph, at 9:00 a.m. Andy is at the point (0,0), which is the begining of the trail. Hence, he is at the trail start.
2) Who runs fastest?
Bertha
If we observe the slopes of each line; Bertha's slope has the least steep. This means she is displacing more in less time, than the other two runners.
3) When do Andy and Berta cross paths?
After 8 minutes, on mile 1.
According to the graph, exactly at the point (8,1), which is at 9:08 a.m. and in mile 1; is when the paths of both runners intercept each other.
4) Who is closest to the 1.5 mile mark after 6 minutes?
Bertha
As we see in the graph, at 9:06 a.m Bertha is closest to the 1.5 mile mark, since her line is closest to this point at that time.