very carefully. you need to be a monk first, it's just that hard..
Distance vs. Time
All linear graphs have a straight line and the equation: y = mx + c, where m is the gradient of the line and c is the y-axis intersection point.
Sometimes you just have to take the trouble to do the actual graphing, since the results can often be quite unexpected. On the other hand, you should learn to recognize some common forms,...
The graph will be that of a straight line with the basic form of y=mx+b.