Answer:
Option (G)
Step-by-step explanation:
Let the length of the race = a miles
Since, Speed = 
Time taken to cover 'a' miles with the speed = 12 mph,
Time taken '
' = 
Time taken to cover 'a' miles with the speed = 11 mph,
Time taken '
' = 
Since the time taken by David to cover 'a' miles was 10 minutes Or
hours more than the time he expected.
So, 



a = 22 mi
Therefore, distance of the race = 22 mi
Option (G) is the correct option.