Question 26368
Rate on the freeway = x
Rate on the side road= x+9
{{{20/x+9=15/x}}} ---> cross multiply

15(x+9)=20x
135+15x=20x
5x=135
x=27
27+9=36


Hence, his rate on the side road is 36mph and rate on the freeway is 27mph.
Paul.