To find the driver's time, you set up a conversion factor/proportion.
200 miles · [tex]\frac{1 hour}{168.7 miles}[/tex]
Having "miles" on both the top and bottom cause them to cancel each other out. Only variable you are left with is hours.
Multiply across. Now, use your calculator to find 200/168.7
200/168.7 ≈ 1.1855
It took the driver approximately 1.1855 hours to complete the 200-mile race.