Let w = the walking time
the total time is given as 1 hr, therefore (1-w) = running time
Walking dist and running dist is the same
Write a distance equation: dist = speed * time
3w = 9 (1-w)
3w = 9 - 9w
3w + 9w = 9
12w = 9
w = 9/12 = 3/4 hrs walking back