Question 745393
Distance up and distance down are same.

r*t=d, t=d/r

Up hill:  4*x=d
Down hill: 6*y=d
4x=6y
x+y=3 hours.


The description yields the system:
{{{4x=6y}}} and {{{x+y=3}}}
Just solve this system for x and y.
x is how much time up the hill.