Francisco P. answered • 10/06/14

Rigorous Physics and Math Tutor

Elisabeth runs 5 miles in 45 minutes or she runs 1 mile in 9 minutes if you divide out 5.

We can set up the proportion either using 9/1 = x/7 or 7/1 = x/9.

So, x = 63 minutes for 7 miles using either proportion.

For a marathon, if she runs at the same pace, we can use the same setup to find the time.

9/1 = x/26 or 26/1 = x/9