20 miles per hour
1) Gathering the data from the question:
S=140 miles
Time spent =7 hours
Average speed=?
2) The average speed is calculated using a ratio:
[tex]A\text{ =}\frac{140}{7}=\text{ 20}[/tex]Since the units are in a standard usual way, we don't need to do any conversion so, the answer is
20 miles per hour
