Question 403723

let distance be x km
while going to meet 4km/h
time taken = x/4
...
return speed = 5km/h
time = x/5
...
x/5 +x/4 = 54/60
(4x+5x)/20=54/60
9x=54*20/60
9x=18
/9
x= 2km====> distance friend lives