Cartesian graph

Question

Imagine that a line on a Cartesian graph is approximately the distance y in feet a person walks in x hours. What does the slope of this line represent? How is this graph useful? Provide another example for your colleagues to explain.

Answer 1

The slope of the line gives you feet/hour that a person is walking. The graph is useful because you can derive a function from it to describe how far a person will travel given any length of time. 

Answer 2

The slope is the speed.  The y-intercept, which is the place where the locus of the equation (the "graph") crosses the y-axis, is how far away (from somewhere - not defined in the description) the person was when s/he started walking.  The graph then allows someone to see where this person would be at any point in time (assuming that point in time is graphed).