Andrea has 6 hours to spend training for an upcoming race. She completes her training by running ful

Andrea has 6 hours to spend training for an upcoming race. She completes her training by running full speed the distance of the race and walking back the same distance to cool down. If she runs at a speed of 7mph and walks back at a speed of 3mph, how long should she plan to spend walking back?

Let the distance be d.

Running full speed one way, 7d
Walking back the opposite way, 3d

And we know 7d + 3d = 6 hours
10d = 6 hours

d =3/5 hour