The problem statement gives you the relationship between their speeds, and it gives you information you can use to find their total speed. You solve this by finding the total speed, then the proportion of that belonging to Bill.
The total speed is (120 mi)/(3 h) = 40 mi/h.
The speed ratio is ...
... Bill : Joe = 3 : 1
so the speed ratio Bill : Total is ...
... 3 : (3+1) = 3:4.
Bill's speed is (3/4)×(40 mi/h) = 30 mi/h.
The graph is shown in the attached image.
Answer:
on the number line make an open circle at 80 (am open circle is this: ○) and connect that to an arrow that points back to 0 and the negative numbers. It doesn't matter how far back as long as you make it an arrow
