Final answer:
The answer of 4/5 of a mile is reasonable because it is close to a full mile when considering additional information from the problem.
Step-by-step explanation:
When Eric solved the problem, he got 4/5 of a mile as his answer. To determine if this is a reasonable answer, we can consider some additional information from the problem. If we travel 10 km in a third of an hour (20 minutes), we would travel three times that distance in an hour. Therefore, the answer of 4/5 of a mile does seem reasonable because it is close to a full mile.