SOLUTION: Car A travels 180 miles in the same time it takes Car B to travel 120 miles. If one car is going 20 mph faster than the other car, find both speeds.

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Car A travels 180 miles in the same time it takes Car B to travel 120 miles. If one car is going 20 mph faster than the other car, find both speeds.       Log On


   

Question 306483: Car A travels 180 miles in the same time it takes Car B to travel 120 miles. If one car is going 20 mph faster than the other car, find both speeds.
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT
180=(R+20)T
T=180/(R+20)
120=RT
T=120/R
SET THE 2 T EQUATIONS EQUAL.
180/(R+20)=120/R CROSS MULTIPLY.
180R=120(R+20)
180R=120R+2,400
180R-120R=2,400
60R=2,400
R=2,400/60
R=40 mph. for the slower car.
40+20=60 mph. for the faster car.
Proof:
180/60=120/40
3=3 ans. for the travel time.