Final answer:
Mary's running speed is 5 miles per hour, represented by the fraction 10/2, which simplifies to 5/1. Her biking speed is 20 miles per hour.
Step-by-step explanation:
Mary wants to calculate her running and biking speeds in miles per hour. Since she completed a 10-mile race in 2 hours, her running speed is the distance divided by the time taken. To calculate Mary's running speed, we use the formula speed = distance / time. In this case, it's 10 miles / 2 hours, which equals 5 miles per hour (mph).
The fraction that represents Mary's running speed in miles per hour is therefore 10/2, which simplifies to 5/1.
For biking, if Mary can bike the same distance in half an hour (0.5 hours), her biking speed would be 10 miles / 0.5 hours, which equals 20 miles per hour (mph).