SOLUTION: Please help! A car travels 304 mi. A second car, traveling 9 mph faster than the first car, makes the same trip in 1 h less time. Find the speed of each car. First Car? Second

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Please help! A car travels 304 mi. A second car, traveling 9 mph faster than the first car, makes the same trip in 1 h less time. Find the speed of each car. First Car? Second      Log On


   



Question 1113418: Please help!
A car travels 304 mi. A second car, traveling 9 mph faster than the first car, makes the same trip in 1 h less time. Find the speed of each car.
First Car?
Second Car?

Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let r be the speed of the slower car, in mph


Then the speed of the faster car is (r+9) mph.


The "time equation" is

304%2Fr - 304%2F%28r%2B9%29 = 1     ("second car, traveling 9 mph faster than the first car, makes the same trip in 1 h less time")


304*(r+9) - 304r = r*(r+9)

2736 = r^2 + 9r

r^2 + 9r - 2736 = 0

(r-48)*(r+57) = 0


The only positive root is  r= 48 mph.


It is the speed of the slower car.


Answer.  The speed of the slower car is 48 mph;  of the faster car  48+9 = 57 mph.

Solved.