Calculating average speeds when distance is unknown

[BogMonkey]

I found a brilliant website with physics questions + solutions here
http://www.solvephysics.com/problems_kinematics.shtml [Broken]
the question I'm on they only tell you the speed traveled in fractions of the total distance but don't tell you the total distance. I looked at the solution but couldn't make much sense of where they got this from

heres the solution page
http://www.solvephysics.com/kinematics_problem86.shtml

 

[diazona]

You know $v = d/t$, right? That can be rearranged to $t = d/v$. Then just plug in values for that quarter of the journey.