Question 347029
let store distance be x mph
speed = 4.5 mh
time taken = x/4.5 hours
..
return from store
time = x/3 hours
..
x/4.5 + x/3 = 1
(3x+4.5x)  /4.5*3 =1
7.5x= 4.5*3
7.5x = 13.5
x= 13.5/7.5
x= 1.8 miles
...
distance = 1.8 miles
speed = 4.5 mph
time = 1.8/4.5 hours
time to walk to store = 0.4 hours = 24 minutes