Question 71034
DISTANCE=RATE*TIME SO TIME=DISTANCE/RATE
20/(X+10)=15/X CROSS MULTIPLY
20X=15(X+10)
20X=15X+150
20X-15X=150
5X=150
X=150/5
X=30 MPH ON THE FREEWAY THUS 
30+10=40 MPH ON THE SIDE ROADS.