EXPLANATION
Since the average speed is given by the equation:
[tex]s(t)\text{ = }\frac{60}{t}[/tex]Computing s(10) and s(12):
[tex]s(10)\text{ = }\frac{60}{10}=6[/tex]Now, computing s(12):
[tex]s(12)=\frac{60}{12}=5[/tex]In conclusion, the solutions are:
s(10) = 6 miles per hour
s(12) = 7 miles per hour