(BEST ANSWER GETS MEDAL!) Two cars leave town A at the same time and travel to town B, 480 miles away. The speed of the slower car is 20 mph less than the speed of the faster car. If the slower car arrives at town B two hours after the faster car, what is the speed of the slower car?

Question

perl · Answer

you can use equation 
d = r* t 
car 1:
d1 = r1 * t1 
car 2 :
d2 = r2* t2

We are given that d1 = d2 = 480

assume car 2 is slower car
therefore
r2 = r1 - 20
t2 = t1 + 2

perl · Answer

substituting we get
480 = r1 * t1 
480 = (r1 - 20 ) ( t1 + 2)

anonymous · Answer

Ahh thank you so much! Can you help me with another problem too? :)

perl · Answer

whats the speed of the slower car?

anonymous · Answer

um not quite sure how to do that I just realized...

perl · Answer

you need to solve that system of equations

you can plug the system of equations into wolfram

anonymous · Answer

okay one second

perl · Answer

http://www.wolframalpha.com/input/?i=solve+480+%3D+r1+*+t1%2C+480+%3D+%28r1+-+20+%29+%28+t1+%2B+2%29