You need to set up a linear graph. One side with gallons and the other with dollars. Point 1 will be at (1500, 2.10). Point 2 (1300, 2.95). Draw a straight line through these points in your graph and your graph will then give you the answers to your other questions.
Answer:
any number from 6 and above
1. 1/10
2. 3/5
3. 1/10
4. 1/6
5. 3/14
Step 1
Collinear points are a set of three or more points that exist on the same straight line. Collinear points may exist on different planes but not on different lines.
Step 2
Graph the points; (-5,2),(0,6),(6,4)
Step 3
Conclude based on step 2
Since the points are not a straight line, we can conclude that the 3 points are not collinear.