Answer:
Option 2 is the correct answer.
Step-by-step explanation:
We know that
[tex]Speed=\frac{Distance}{time}[/tex]
We have 1 mile = 5280 feet thus 6 miles = 31680 feet
Similarly 1 hour = 3600 seconds
Applying values in the equation above we get
[tex]Speed=\frac{31680feet}{3600sec}\\\\Speed=8.8feet/sec[/tex]
Thus his average speed is less than 18feet/sec