A. The function must be non-linear because he constantly changes his speed and pauses at some places. For it to be linear he would have to be going at a constant rate the entire time.
B. Plot the point (20, 1.2), draw a line from (0,0) to it. Then plot (30, 1.2), because he stays there for 10 minutes. Now plot the point (60, 2.5) because it takes him 30 minutes to walk 1.3 miles to the park. Then plot the point (75, 2.5) because he stays there for 15 minutes. Lastly, plot the point (120, 5) for his return home. Be sure to connect these points together with lines.