Question

A plane that carries mail makes a round trip each day from Chicago to New York. It makes 3 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

Answer 1

7 times the graph will touch the horizontal axis

Explanation:

It flow from Chicago to first intermediate stop, Number of times on the horizontal axis 1.

1st intermediate stop to 2nd intermediate stop, Number of times on the horizontal axis 2.

2nd intermediate stop to 3rd intermediate stop, Number of times on the horizontal axis 3.

3rd intermediate stop to New York, Number of times on the horizontal axis 5.

Return

New York to 1st intermediate stop, Number of times on the horizontal axis 6.

1st intermediate stop to Chicago, Number of times on the horizontal axis 7.

Answer 2

If we assume that we're measuring altitude from ground level (as opposed to sea level), there will be x-axis touches for ...

• Chicago (the starting point for the day)
• stop 1
• stop 2
• stop 3
• New York
• stop 4
• Chicago (the ending point for the day)

The graph will touch the horizontal axis 7 times.