Hello!
You run 5 miles a hour
To find how far you go in half an hour you divide the distance by 2
5 / 2 = 2.5
To find how far you go in 2 1/2 hours you multiply the distance by 2.5
5 * 2.5 = 12.5
The answers are 2.5 miles in half an hour and 12.5 miles in 2 1/2 hours
Hope this helps!