A plane that carries mail makes a round trip each day from Chicago to New York. It makes 2 intermediate stops on the way to New York and 1 intermediate stop on the way back to Chicago. Suppose you make a graph of the altitude of the plane for one day, with time on the horizontal axis and altitude on the vertical axis. How many times will the graph touch the horizontal axis?
1 answer
The graph of the altitude of the plane will touch the horizontal axis 6 times in total. This is because the plane will touch the horizontal axis at each of the 4 intermediate stops, once when landing in New York and once when landing in Chicago.