SOLUTION: Robert can drive 40 miles using the side roads in the same time that it takes to travel 30 miles on the freeway. If Robert's rate on the side road is 7 miles an hour faster than hi

Question 103379: Robert can drive 40 miles using the side roads in the same time that it takes to travel 30 miles on the freeway. If Robert's rate on the side road is 7 miles an hour faster than his rate on the freeway, find his rate on the side road. I need help contructing the equation to solve for the rate. I am confused because there is no time given.
Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
let x=rate on side roads ... in the same time, he can only go 3/4 as far on the freeway, so the freeway rate is (3/4)x

(3/4)x+7=x ... 7=(1/4)x ... 28=x

using t=d/r ... the times are the same so 40/r=30/(r-7)

cross multiplying gives 40r-280=30r ... 10r=280 ... r=28
RELATED QUESTIONS
im stuck-please help-During rush hour, Fernando can drive 40 miles using the side roads... (answered by Paul)

During rush hour, Fernando can drive 40 miles using the side roads in the same time that... (answered by josmiceli)

During rush hour, Fernando can drive 40 miles using the side roads in the same time that... (answered by ankor@dixie-net.com)

During rush hour, Fernando can drive 40 miles using the side roads in the same time that... (answered by scott8148)

During rush hour, Adriana can drive 40 miles using the side roads in the same time that... (answered by scott8148,Edwin McCravy)

During rush hour, Ella can drive 40 miles using the side roads in the same time that it... (answered by ptaylor)

During rush hour,adriana can drive 30 miles using the side roads in the same time that it (answered by ptaylor)

During rush hour, Fernando can drive 35 miles using the side roads in the same time that... (answered by ptaylor)

During rush hour, Adriana can drive 30 miles using the side roads in the same time that... (answered by ankor@dixie-net.com)