Question 946903
First part was downhill, and second part was uphill.
R=12
r=3
T=23 hours, total trip time
D=213 miles, total trip distance


This could be set up in one unknown variable, but it is done here using two unknown variables:
u, the time downhill
v, the time uphill


________________speed___________time____________distance
FIRST___________R________________u______________Ru
SECND___________r________________v______________rv
Total____________________________T_______________D


Fundamentally, {{{rate*time=distance}}}.