Final answer:
The length of the race could be any whole number of kilometers between 150 and 200.
Step-by-step explanation:
When rounding the length of the race to the nearest 100 kilometers, it is 200 kilometers. When rounding to the nearest 10 kilometers, it is 150 kilometers. So, a possible value for the length of the race could be any whole number of kilometers between 150 and 200.