SOLUTION: A car travels to and from a city 72km away in 2 hours. If the average speed on the return trip is 30km/h less than the trip to the city, what was the average speed of the car when

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A car travels to and from a city 72km away in 2 hours. If the average speed on the return trip is 30km/h less than the trip to the city, what was the average speed of the car when       Log On


   



Question 840602: A car travels to and from a city 72km away in 2 hours. If the average speed on the return trip is 30km/h less than the trip to the city, what was the average speed of the car when it was going toward the city?
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
a+b=2,
a*x=72,
b*(x-30)=72
a = 4/5=.8, b = 6/5=1.2, x = 90 kmh towards the city
check
.8*90=72
1.2*60=72
ok