Question 23840
Let the rate on the freeway be represented by x.
He drives 40 miles on the side road.
In same time he drives 30 miles on freeway.
Rate on the side road = 7+x
Rate on the freeway = x


Since 40 miles on side road and speed 7+x: expression = 40/(x+7)
Since 30 miles on freeway with the speed x: expression = 30/(x)


{{{40/(x+7) = 30/(x)}}} ---> cross multiply
30(x+7)=40x
30x+210=40x
210=10x
x=21


21+7=28


30(21+7)=40(7)
280=280


Hence, his speed on the freeway was 21mph, on the side road is; 28mph, with total distance traveled ---->280 miles.