Posted by Margie!! on .
Two cars leave town going opposite directions. One car is traveling 55 mph, and the other is traveling 65 mph How long will it take before they are 180 miles apart?
Hint: The time for both cars is the same and can be represented by "t." The total distance is 180 miles. The distance = (rate)(time). If you add the (rate)(time) of the first vehicle to the (rate)(time) of the second vehicle, that will equal the total distance of 180 miles. Since you only have one unknown (t), you only need one equation.
*I don't get it at ALLL!
The relative speed is 55+65. That is the speed between the cars.
distance between cars= relative speed*time
solve for time.
So the answer is....
120?
solve for time
time= distance/relative velocity
pay attention to the equations, let them do the work. You are grasping at just plain answers. Anybody can write down answers.

Algebra! 
bidickjophnson,
m8

Algebra! 
Shay,
Two cars leave the same town at the same town. One travels west at 60 mph and the other at 45 mph. In how many hours will they be 420 miles apart?