Chapter 4.2, Problem 89E

Average Speed A driver’s average speed is 50 miles per hour on a round trip between two cities 100 miles apart. The average speeds for going and returning were $x$and $y$miles per hour, respectively.

(a) Show that $y=\frac{25x}{x-25}$.

(b) Determine the vertical and horizontal asymptotes of the graph of the function.

(c) Use a graphing utility to graph the function.

(d) Complete the table.

(e) Are the results in the table what you expected? Explain.

(f ) Is it possible to average 20 miles per hour in one direction and still average 50 miles per

hour on the round trip? Explain.