Question 974580
Generalization in this data table



_____________________speed___________time___________distance
UPST_________________r-c_____________u______________d
DOWN_________________r+c_____________v______________d
Total________________________________t



Uniform Rates, Travel,  RT=D relating rate, time, distance.


The known variables are c, d, t.
Not known either are u and v.


{{{system((r-c)u=d,(r+c)v=d,u+v=t)}}}


Solve your system for r.